Physical activity, cardiorespiratory fitness, and health

·       Research methods of assessment of the effects of physical activity on health (and in particular mortality) include (1) estimating physical activity or (2) objectively measuring physical activity (Editorial. JAMA. 2006. 296. 216-218).

o   Estimates of physical activity include self reports of physical activity, job classifications, and measurement of cardiorespiratory fitness.

§  Self report questionnaires may not include appropriate questions to fully capture all relevant activities, or individuals may have inadequate or inaccurate recall.

§  Individuals working within the same job classification may have widely varying levels of energy expenditure.

§  Cardiorespiratory fitness is an objective measurement, but reflects physical activity only in the weeks and months prior to the measurement, and is affected also by genetics.

o   Objective measurements of physical activity – accelerometry and doubly labeled water.

·       Physical activity as objectively measured over 2 weeks by doubly labeled water is strongly associated with a lower risk of mortality in healthy older adults, based on data gathered in 302 high-functioning, community-living older adults aged 70-82, and followed for a mean of 6.15 years (JAMA. 2006. 296. 171-179).

·       The DREW (dose response to exercise in postmenopausal women) study was specifically designed to examine the effect of 3 different exercise ‘doses,’ 4, 8, or 12 kcal/kg/week on cardiorespiratory fitness in sedentary, overweight or obese women with elevated BP. ) In this 6 month intervention trial in 464 women, with target training intensity set as the heart rate associated with 50% of VO2max, there was good adherence and  follow up. The average number of exercise sessions per week was only 2.6 – 3.1, but the exercise groups carried out 72, 136, and 192 minutes of exercise per week, corresponding to approximately 50%, 100%, and 150% of the NIH Consensus Panel physical activity recommendations (30 minutes of moderate –intensity physical activity on most days. A graded dose-response change in fitness was observed, with some improvement in fitness documented with as little as 72 minutes of exercise per week, and with no significant influence of race or baseline weight on the relationship between exercise and fitness (JAMA. 2007. 297. 2081-2091 and editorial 2137-2139).


Aerobic exercise (i.e. walking, jogging, swimming, cycling, aerobics)

·       Old wisdom: minimum of 20-30 minutes of continuous exercise 3-4 times/week at 70-85% of maximum heart rate is necessary to achieve fitness (training effect) which is defined physiologically by parameters such as VO2 maximum, resting heart rate, endurance, and time to recovery of resting heart rate.

·       New wisdom: any exercise is better than no exercise.

o   Total exercise:  there seems to be a dose - response curve between total exercise/wk and health benefits. Small amount of activity (500-1499 kcal/wk) yields 23% lower death risk, moderate amount of activity (1500-2499 kcal/wk) yields 38% lower death risk, large amount of activity (2500-3500 kcal/wk) yields 50% lower death risk.  Benefits plateau above 3500 kcal/wk. Even small amounts of activity can also improve blood pressure, cholesterol, and weight.

o   Intensity: 

§  Low intensity exercise is associated with some improvement in VO2 maximum, lipids, blood sugar, blood pressure, weight, life expectancy, and psychological well-being. 

§  Low intensity exercise of long duration actually seems to be superior to high intensity exercise with regard to improvements in blood pressure, blood sugar, and psychological well-being, as well as more efficient modulation of fat metabolism.  There is also may be less free radical production with low intensity exercise.

§  There is emerging evidence that interval training (short bursts of high-intensity exercise with gentle recovery during workout regimens) at least once a week can improve cardiovascular fitness and the body's fat-burning capabilities (J Appl Physiol. 2007. 102. 1439-1447).

§  There is data that high intensity interval walking is associated with increases in thigh muscle strength (p<0.001), increases in peak aerobic capacity (p<0.001), and decreases in resting BP (p=0.01), compared with no walking training. Furthermore, the increases in thigh muscle strength and peak aerobic capacity are greater with high intensity interval walking as compared with moderate intensity continuous walking (p<0.01). In this study, the continuous walking group was instructed to walk at 50% of peak aerobic capacity for 8000 steps or more per day for 4 or more days of the week, and targets were met by 8 of 16 men and 43 of 59 women randomized to this group. The high intensity interval walking group was instructed to repeat 5 or more sets of 3 minutes of low intensity walking at 40% of peak aerobic capacity, followed by 3 minutes at 70% of peak aerobic capacity, and targets were met by 11 of 19 men and 31 of 68 women randomized to this group (Mayo Clin Proc. 2007. 82. 803-811).

o   Duration:  it now seems that three 10 minute bouts of exercise are as good as one 30 minute bout in terms of improving fitness.

o   Frequency:  daily low intensity exercise is probably better than 3-4 times/wk with regard to lowering blood pressure. Current national policy calls for 30 minutes of physical activity every day for all adults.

·       Cross-training (rotating the type of exercise) reduces the incidence of overuse injury and helps prevent burnout.

·       Too much exercise can be detrimental, especially in women.

o   Triad:  disordered eating, amenorrhea, osteoporosis.

o   Treatment:  lifestyle changes, oral contraceptive, or hormone therapy.

·       In general, aerobic exercise raises cortisol and adrenalin levels.


Benefits of aerobic exercise

·       Mortality and morbidity– reduces total mortality and reduces morbidity

o   Morbidity

§  In 1,097 persons dying in late old age, the OR for increased likelihood of dying without disability among the most physically active group was 1.86, compared with sedentary adults (Am J Epidemiol. 1999. 149. 654).

§  Data in 13,535 participants in the Nurses’ Health Study who were free of major chronic diseases at baseline in 1986 and had survived to age 70 or older as of 1995-2001 showed that “higher levels of midlife physical activity are associated with exceptional health status among women who survive to older ages” (Arch Intern Med. 2010. 170. 194-201).

o   Mortality

§  Reductions in total mortality documented in Harvard alumni (N Engl J Med. 1986. 314. 605-613), a study in men in Honolulu (N Engl J Med. 1998. 338. 94) and in Puerto Ricans (Ann Epidemiol. 2002. 12. 543-552).

§  Analysis of data from the Framingham Heart Study cohort of 2236 male and 2873 female respondents from 1948-1951, followed biannually for 46 years, shows that life expectancy is increased by 1.3 years in men 50 years or older who have engaged in moderate physical activity, 3.7 years in men 50 years or older who have engaged in high physical activity, 1.5 years in women who have engaged in moderate physical activity, and 3.5 years in women who have engaged in high physical activity.  There were similar increases (1.1 years, 3.2 years,  1.3 years, and 3.3 years respectively) in years lived free of cardiovascular disease (Arch Intern Med. 2005. 165. 2355-2360).

§  NOTE that while exercise is important, data in 222,497 adults in the 45 and Up Study, a large prospective cohort study in New South Wales, indicates that “Prolonged sitting is a risk factor for all-cause mortality, independent of physical activity” (Arch Intern Med. 2012. 172. 494-500).

·       May preserve telomere length in chromosomes (and shortening of telomeres is associated with aging) based on German research in runners cited in Consumer Reports on Health, March 2010.


·       Alzheimer’s disease – reduced risk correlated with regular exercise; reduced risk associated with midlife cardiorespiratory fitness (See also ‘mild cognitive impairment)

o   Biological plausibility – improves cerebral blood flow and oxygen delivery (J Am Geriatr Soc. 1990. 38. 123-128), induces fibroblast growth in the hippocampus (Neuroscience. 1998. 85. 53-61), upregulates proteins that stimulate neural growth, and increases brain-derived neurotrophic factor (BDNF) in the hippocampus (Trends Neurosci. 2002. 25. 295-301; Neurobiology Aging. 2005. 4. 511-520).

o   Reduced risk of 20% (Neurology. 2001. 57. 2236-2242) to 50% (Arch Neurol. 2001. 58. 498-504) seen over follow up periods of 5-7 years in observational studies. Reduced risk of dementia seen in association with exercise in 6 of 9 observational studies, based on a published review article (Lancet Neurol. 2004. 3. 343-353).

o   In the Honolulu Asia Aging Study, older men who walked more than 2 miles per day had a 40% lower risk for dementia than those who walked less (JAMA. 2004. 292. 1447-1453).

o   In the Cardiovascular Health Cognition Study, the variety of exercise activity in later life was a stronger predictor of a lower risk of dementia than the energy expenditure in physical activity. Relative risk of dementia at 5.4 years of follow-up in the 3375 adults in this study was 0.85 in those in the highest quartile of energy expenditure versus the lowest quartile (difference not statistically significant) whereas the relative risk for those engaging in > 4 activities was 0.51 compared with those participating in 0-1 activities (Am J Epidemiol. 2005. 161. 639-651).

o   In a Finnish study, leisure time physical activity in middle age was associated with a lower risk of dementia in old age (Lancet Neurol. 2005. 4. 705-711).

o   In a prospective cohort study of 1740 individuals over age 65 without cognitive impairment at baseline and who scored above the 25th percentile on a cognitive ability screening instrument, at a mean follow-up of 6.2 years those who exercised more than 3 times per week by self report had a 30% lower risk of Alzheimer’s disease than those who exercised less than 3 times per week (Ann Intern Med. 2006. 144. 73-81).

o   In a RCT in 170 volunteers over age 50 (average age of 68) who reported memory problems but did not meet criteria for dementia, those randomized to a 24 week home-based program of physical activity showed statistically significant improvement in cognition at 18 months of follow up. The mean improvement in the 70 point scale used was 0.73 points in the treatment group versus 0.04 points in the control group, so while the results were statistically significant, the patients, families, and clinicians could not easily detect a clinical benefit. However, there were no significant adverse effects of the treatment regimen  (JAMA. 2008. 300. 1027-1037 and editorial 1077 and 1079).

o   A trial in which activity energy expenditure was calculated (using doubly labeled water) in 197 men and women, mean age 74.8 years, and free of mobility and cognitive impairments, and in which cognitive function was assessed via MMSE at baseline, 2 years, and 3 years, found a significant dose response between activity energy expenditure at baseline and cognitive impairment 2-3 years later (Arch Intern Med. 2011. 1251-1257).

o   Prospective observational data in19,458 community-dwelling nonelderly adults in the Cooper Center Longitudinal Study found that higher midlife cardiorespiratory fitness was correlated with a lower risk of developing all-cause dementia  later in life (CCLS) (Ann Intern Med. 2013. 158. 162-168 and editorial 213-214).

·       Anxiety

o   Reduces anxiety in otherwise well adults – multiple published studies and meta-analyses (J Appl Sport Psychol. 1995. 7. 167-189; Anxiety Stress Coping. 1994. 6. 275-288; Sports Med. 1991. 11. 143-182).

o   Reduces anxiety symptoms in patients with chronic conditions, based on a systematic review (Arch Intern Med. 2010. 170 .321-331).

·       Asthma - a 3 month RCT in 101 asthmatics receiving pharmacological therapy and who were clinically stable for at least 30 days showed that those randomized to twice weekly 30 minutes sessions of aerobic training had significantly more symptom-free days (24 versus 16 per month, p<0.001) and significant improvements in anxiety and depression scores from baseline (p<0.001) whereas the control group did not show improvement in these symptom scores. Finally, those in the aerobic training group showed significant improvement in total asthma-related quality of life scores (p<0.001). The improvements in the treatment group correlated with improvement in aerobic capacity – pulmonary function testing showed no significant change in pulmonary function in the exercise group (Mendes FA et al. Chest. 2010. 138. 331).

·       BPH – in a study in 25,500 men, the relative risk for BPH was 0.75 for men in the highest quintile of physical activity versus sedentary men (Arch Intern Med. 1998. 158. 2349).

·       Breast cancer

o   Prospective data in 100,697 postmenopausal women in the Nurses Health Study (more than 20 years of follow up) showed that moderate physical activity (average of 27 MET hours per week), including brisk walking, is associated with a 15% reduced risk of postmenopausal breast cancer, as compared with sedentary women. Reduced risk was seen for both hormone receptor positive and hormone receptor negative breast cancer (Arch Intern Med. 2010. 170. 1758-1764 and Commentary 1792-1793).

o   Prospective data in 64,777 premenopausal women in the Nurses Health Study II showed that leisure-time physical activity is associated with reduced risk of premenopausal breast cancer (J Natl Cancer Inst. 2008. 100. 728-737).

o   Improves outcomes in breast cancer, based upon retrospective analysis of 2987 women in the Nurses’ Health Study - those who exercised 3-8.9 MET-hr/wk had a 20% decreased risk of death from breast cancer and those who exercised 9-14.9 MET-hr/wk (walking 3-5 hours per week at an average pace) had a 50% decreased risk.  There was no benefit to more exercise.  Benefit was greatest in those with ER-positive and PR–positive tumors (JAMA. 2005. 293. 2479-2486).

o   Retrospective analysis of 2987 women in the Nurses’ Health Study found that those who exercised 3-8.9 MET-hr/wk had a 20% decreased risk of death from breast cancer and those who exercised 9-14.9 MET-hr/wk (walking 3-5 hours per week at an average pace) had a 50% decreased risk.  There was no benefit to more exercise.  Benefit was greatest in those with ER-positive and PR–positive tumors (JAMA. 2005. 293. 2479-2486).

o   Reduced risk seen in (seminal) prospective cohort study (N Engl J Med. 1997. 336. 1269-1275).

o   Secondary prevention

1.     In a meta-analysis of 14 RCTs (n=717) physical activity in breast cancer survivors was associated with significant improvements in quality of life and physical functioning (CMAJ. 2006. 175. 34-41).

2.     In a meta-analysis of 6 prospective cohort studies including over 12,000 breast cancer survivors, postdiagnosis physical activity was associated with 24% lower recurrence rate and 34% lower breast cancer mortality (Med Oncol. 2011. 28. 753-765).

3.     Data gathered on lifelong recreational activity habits of 1500 women diagnosed with breast cancer showed that moderate intensity lifetime activity was associated with a lower mortality at 5 years of follow up (Eur J Cancer Prevent. 2011).

·       CAD

o   Cardiorespiratory fitness is a surrogate marker for numerous heart outcomes, including morbidity and mortality (JAMA. 1996. 276. 205-210; Am J Cardiol. 2001. 88. 651-656), and would suggest a linear, inverse dose-response relationship such that higher levels of physical activity are associated with further reduction in cardiovascular morbidity and mortality (Med Sci Sports Exerc. 2001. 33. S351-S358; Med Sci Sports Exerc. 2001. 33. S379-S399).

o   For more information, go to Home Page and click on MI Prevention and scroll down to ‘Exercise.’

o   Mechanism: in part by lowering BP, in part by lowering cholesterol, and in part by bring about regression of left ventricular hypertrophy (Arch Intern Med. 2002.162. 1333-1339).       

o   A Review Article of “Effects of Physical Activity on Cardiovascular Disease” concludes that “the data show a correlation between physical activity and triglyceride reduction, apolipoprotein B reduction, high-density lipoprotein increase, change in low-density lipoprotein particle size, increase in tissue plasminogen activator activity, and decrease in coronary artery calcium” (Am J Cardiol. 2012. 109. 288-295).

·       Cancer

o   Epidemiologically, reduced cancer risk seen in those who exercise regularly – as per Christine Friedenreich, PhD (interview in AICR News Summer 2011), physical activity reduces the risk of breast, colon, and endometrial cancer by 25-30%, and lung, ovarian, and prostate cancers by 10-30%. Presumed mechanisms – effects on body fat, sex steroid hormones, chronic inflammation, and insulin resistance.

o   A number of small studies show benefits of exercise during and after cancer treatment (Alt Med Alert. 2006. 9. 137-140).

o   In a cohort of 668 men in the Health Professionals Follow-up Study with a history of stage I – III (nonmetastatic) colorectal cancer, more physical activity was associated with a lower risk of colorectal cancer specific and overall mortality (Arch Intern Med. 2009. 169. 2102-2108).

·       CHF

o   Beneficial in a 24 week trial (Ann Intern Med. 1996. 124. 1051-1057).

o   Beneficial in a 16 week RCT in 80 patients (Am J Cardiol. 2008. 102. 1361-1365).

o   Beneficial in the HF-ACTION trial, a multi-center RCT in 2331 patients with chronic systolic heart failure, NYHA class II – IV, in which the treatment group consisted of 36 supervised sessions, followed by home-based training. Median follow-up was 30 months.

1.     Modest significant reductions in the endpoints of (1) all-cause mortality or hospitalization AND (2) cardiovascular mortality or heart failure hospitalization, after adjustment for highly prognostic predictors for the primary endpoint (JAMA. 2009. 301. 1439-1450). These findings are consistent with the results of 33 previous trials, mostly small single-center trials.

2.     Modest significant improvement in self-reported health status, which occurred early in the trial and persisted over time (JAMA. 2009. 301. 1451-1459).

o   A ten year supervised exercise training program improved peak oxygen consumption and quality of life, and reduced hospital readmissions, compared with usual physical activity in an Italian RCT of 123 patients with an ejection fraction < 40% (J Am Coll Cardiol. 2012. 60. 1521-1528).

o   Aerobic interval training is more effective than moderate intensity continuous training for improving peak VO2, but not for improving LVEF at rest, based on a meta-analysis of 7 RCTs conducted in clinically stable patients with heart failure with reduced ejection fraction (Am J Cardiol. 2013. 111. 1466-1469).

·       Cholesterol

o   Consistent aerobic exercise lowers the cholesterol: HDL cholesterol ratio by 15% (Circulation. 1995. 92. 773-777).

o   A meta-analysis of 25 RCTs shows that (1) a minimum exercise volume of 120 minutes of exercise per week or 900 kcal of energy expenditure per week is necessary to raise HDL, (2) mean net change in HDL is statistically significant but moderate at 2.53 mg/dl, (3) exercise duration per session seems to be the most important factor in determining the effect of aerobic exercise on HDL levels, with every 10 minute prolongation of exercise per session associated with a 1.4 mg/dl increase in HDL, and (4) exercise is most effective in individuals who at baseline have total cholesterol of >220 mg/dl or a BMI < 28 (Arch Intern Med. 2007. 167. 999-1008).

·       Depression

o   Reduces depression in the elderly (Br J Sports Med. 2001. 35. 14-117; Am J Epidemiol. 2001. 153. 596-603).

o   May be effective treatment for mild/moderate depression (Am J Prev Med. 2005. 28. 1).

o   A Cochrane review of 23 RCTs concluded strong evidence of benefit, with the caveat that the effect size was lowest for the 3 RCTs of highest methodologic quality (Cochrane Database Syst Rev. 2009).

o   A systematic review and meta-analysis of 90 RCTs (n=10,534) of exercise for sedentary patients with a chronic illness showed that “Exercise reduces depressive symptoms…” with the greatest benefit seen in those with mild to moderate depression (Arch Intern Med. 2012. 172. 101-111).

·       DM prevention

o   Reduces the risk of developing diabetes (N Engl J Med. 1991. 325. 147-152; JAMA. 1992. 268. 63-67).

o   150 minutes of physical activity per week in conjunction with one-on-one instruction on how to change diet and behavior reduced the risk of onset of diabetes after 2.8 years of follow up, with a number needed to treat of 7 to prevent 1 case of diabetes in 3 years (New Eng J Med. 2002. 346. 393-403).

o   Weight training was associated with a significantly lower risk of developing type II diabetes, independent of the benefit of aerobic exercise, at 18 years of follow up in a cohort of 32,002 men in the Health Professionals Follow Up Study. Combined weight training and aerobic exercise conferred a greater benefit than either alone (Arch Intern Med. 2012. 172. 1306-1312).

·       DM treatment

o   In the Aerobics Centre Longitudinal Study, 12 year cardiovascular and overall mortality were approximately 60% lower in diabetics with moderate to high cardiorespiratory fitness at baseline, compared with those with low baseline fitness (Ann Intern Med. 2000. 132. 605-611).

o   A meta-analysis of 14 controlled trials in diabetics showed that exercise programs had beneficial effects on diabetic control (JAMA. 2001. 286. 1218-1227).

o   A meta-analysis found that aerobic exercise, resistance exercise, and combined aerobic and resistance exercise each improved glycemic control in type 2 diabetics (Diabetes Care. 2006. 29. 2518-2517).

o   A systematic review confirmed that resistance training has beneficial effects on glucose control, also showed that it has beneficial effects on insulin sensitivity and in some studies, lipid profiles (Diabetes Res Clin Pract. 2009. 83. 157-175).

o   In the DARE trial, a 22 week RCT of 251 type 2 diabetics randomized to aerobic training, resistance training, both, or wait-list control, HbA1c was reduced approximately 0.5% with resistance training alone, approximately 0.5% with exercise training alone, and nearly 1% with combined exercise and resistance training. Training was 3 times a week, and was supervised in this trial (Ann Intern Med. 2007. 147. 357-369).

o   In the IDES study, a 12 month multicenter RCT of 606 type 2 diabetics randomized to a treatment group of supervised aerobic and resistance training twice a week for 75 minutes versus a control group which was counseled to increase exercise, those in the treatment group showed improved HbA1c, aerobic fitness, strength, blood pressure, lipid profiles, waist circumference, markers of systemic inflammation, and estimated 10 year cardiovascular risk (Arch Intern Med. 2010. 170. 1794-1803 and editorial 1790-1791).

o   In the HART-D trial, a 9 month RCT in 262 sedentary men and women with type 2 diabetes who were randomized to supervised aerobic training, resistance training, both, or a nonexercise control group, HbA1c improved only in the group randomized to a combination of supervised aerobic and resistance training (JAMA. 2010. 304. 2253-2262).

o   In the EPIC study, in a prospective cohort study of 5859 individuals with diabetes at baseline, higher levels of physical activity were associated with lower mortality risk. The published report of the EPIC study included a meta-analysis of 12 cohort studies; the meta-analysis also found higher levels of physical activity were associated with lower mortality risk (Arch Intern Med. 2012. 172. 1285-1295).

·       Falling episodes – may decrease the incidence in the elderly.

·       Gallstones – decreases the risk of developing gallstones (Ann Intern Med. 1998. 128. 417).

·       GI bleeding – decreases the risk.

·       HTN - decreases blood pressure, with a meta-analysis of randomized, controlled trials concluding that exercise lowers systolic BP by -3.84 mm Hg and diastolic BP by -2.58 mm Hg, with beneficial effects seen in normotensive as well as hypertensive subjects, and normal-weight as well as overweight subjects (Ann Intern Med. 2002. 136. 493-503).

·       Hypercholesterolemia

o   Consistent aerobic exercise lowers the cholesterol: HDL cholesterol ratio by 15% (Circulation. 1995. 92. 773-777).

o   Improves ratio of total cholesterol: HDL cholesterol, and is associated with a graded response in a number of lipoprotein variables, independent of weight loss (N Engl J Med. 2002. 347. 1483-1492).

o   A meta-analysis of 25 RCTs shows that (1) a minimum exercise volume of 120 minutes of exercise per week or 900 kcal of energy expenditure per week is necessary to raise HDL, (2) mean net change in HDL is statistically significant but moderate at 2.53 mg/dl, (3) exercise duration per session seems to be the most important factor in determining the effect of aerobic exercise on HDL levels, with every 10 minute prolongation of exercise per session associated with a 1.4 mg/dl increase in HDL, and (4) exercise is most effective in individuals who at baseline have total cholesterol of >220 mg/dl or a BMI < 28 (Arch Intern Med. 2007. 167. 999-1008).

·       Kidney disease – in a cohort of 4011 ambulatory patients > age 65 in the Cardiovascular Health Study who completed at least two measurements of kidney function over 7 years, high levels of physical activity are associated with a lower risk of decline in renal function (Arch Intern Med. 2009. 169. 2116-2123).

·       Low back pain (chronic) – improves function and reduces pain at 6-12 weeks, 6 months, and 12 months, based on a meta-analysis of 43 RCTs (Ann Intern Med. 2005. 142. 765-775). The most effective programs are individually designed, supervised, and high dose [>20 hr/wk] (Ann Intern Med. 2005. 142. 776-785).

·       Menopause

o   In one study in 793 women age 55-56 who had reached natural menopause, the relative risk for severe hot flashes was 0.26 in the highly physically active women, versus those with little or no exercise (Maturitas. 1998. 29. 139).

o   Observational studies show that women who exercise regularly are less likely than sedentary women to experience severe hot flashes (Acta Obstet Gynecol Scand. 2000. 79. 286-292; Maturitas. 2005. 52. 374-385).

·       Mild cognitive impairment – a 6 month RCT in 16 men and 17 women showed improvement in cognitive function as assessed by standardized testing, with greater improvement in women than men (Arch Neurol. 2010. 67. 71-79).

·       Obesity - helps maintain appropriate weight.

·       Osteoporosis – in a RCT in 246 women age > 65, those assigned to the 18 month exercise program showed significantly improved bone mineral density and a reduced fall risk (Arch Intern Med. 2010. 170. 179-185).

·       PMS - aerobic exercise 30 minutes 3 times a week at 70-85% of maximum capacity associated with a 43% decrease in symptoms in a study in 23 women age 45-55 (J Psychosom Res. 1993. 37. 127).

·       Prostate cancer

o   Data from 47,620 US male health professionals in the Health Professionals Follow-up Study found that although the mechanisms are not understood, the data suggests that regular vigorous activity could slow the progression of prostate cancer and reduce mortality from prostate cancer (Arch Intern Med. 2005. 165. 1005-1010).

o   A meta-analysis of 19 cohort studies and 24 case-control studies overall shows a moderately reduced risk of prostate cancer in association with regular physical activity (Eur Urol. 2011. 60. 1029-1044).

o   Data from the Health Professionals Follow-up study, a prospective observational study of over 2700 men with nonmetastatic prostate cancer, shows that physically active men had significant improvements in all-cause and prostate specific mortality (J Clin Oncol. 2011. 29. 726-731).

·       Stress - modulates stress.

·       Well-being - improves sense of well-being. Mechanism may be in part due to increased dopamine synthesis.


·       Misc:

o   Strengthens pelvic structures in women; decreases risk of prolapse.

o   Prevents functional decline in the frail elderly, based on a 6 month program (New Engl J Med. 2002. 347. 1068-1074).

o   Preserves functional status in older women, based on a 14 year prospective study in 229 women, mean age 74.2 (Arch Intern Med. 2003. 163. 2565-2571). 

o   Activates a hormone, brain-derived neurotrophic factor (BDNF) to repair and potentially trigger development of new nerve cells in the brain.


Facts regarding aerobic exercise

·       80% of Americans don't get enough exercise (2hours/wk).

·       50% of Americans don't exercise at all.

·       50% who begin an exercise program quit within 6 months.

·       Knowledge alone does not keep people exercising.

·       Studies looking at long-term exercisers vs. non-exercisers do not find differences in weight, smoking status, or personality.


Strategy for success - make exercise fun (Jon Robinson)

·       4-6 person teams. Exercise contracts. $40/person into a pot.

·       If failure to meet contract, team loses 50% of money to successful team.

·       137 volunteers - all formerly sporadic exercisers.

·       97% still exercising every other day after 6 months.


Tips for success in starting and staying with an exercise program (Consumer Reports on Health. 5/06).

·       Find opportunities to exercise.

·       Start small and work up.

·       Set a goal.

·       Deal with the details.

·       Make a plan - make it specific – consider writing a contract.

·       Chart your progress and reward yourself - positive reinforcement.

·       Exercise with others - you don't want to disappoint partners.

·       Consider a trainer.

·       Make it enjoyable - cross-train if necessary, hone a skill, dance, go electric, play with toys, pursue active hobbies.

·       Choose a workout that matches your personality – see chart devised by John Gavin, Ph.D.

·       Identify your motivation – social interaction, mental boost, ‘me’ time are all possible motivations.

·       Make it convenient.

·       Have a variety of options.

·       Make it a habit.

·       Take lapses in stride and ‘get back on the wagon.’

·       Expect aches and pains in the beginning.

·       Keep plugging - those who keep exercising for 6 months have a 50-50 chance of making it a long-term habit.


·       Use a pedometer – a systematic review of 26 studies (n=2767) found that “the use of a pedometer is associated with significant increases in physical activity and significant decreases in body mass index and blood pressure.” Eight of the 26 trials were RCTs and the other 18 were observational studies (JAMA. 2007. 298. 2296-2304).


Strategy for success – match fitness activity with personality dimensions

·       Degree of desire for social interaction with fitness activity – team sports at one extreme versus swimming at the other extreme

·       Degree of desire for control versus spontaneity by the participant – team sports at one extreme versus cardio conditioning at the other extreme

·       Degree of extrinsic versus intrinsic motivation to exercise – team sports at one extreme versus cardio conditioning at the other extreme

·       Degree of assertiveness or aggression desired by the participant – racquet sports at one extreme versus tai chi at the other extreme

·       Degree of individuality versus competition versus collaboration desired by the participant – team sports at one extreme versus yoga at the other extreme

·       Degree of mental focus desired while doing the activity – racquet sports at one extreme versus walking at the other extreme

·       Degree of risk taking or thrill seeking desired – downhill skiing at one extreme versus tai chi at the other extreme


Resistance (isometric) exercise (i.e. weight training)

·       Sarcopenia by definition is the loss in muscle mass, related to aging, starts at age 25.

·       Facts and statistics

o   Loss in muscle strength is generally not significant until age 50.

o   Gains in muscle mass are greatest when the routine includes 3 sets of weights at 75-80% of the maximum load that can be lifted once, 3 days/wk. Each set should include 8-12 repetitions. The weight should be lifted over 2-3 seconds; as one breathes out, then lowered over 4-6 seconds as one breathes in.

o   A fitness club offers the ideal setting because of the variety of weight machines and because of the instruction and supervision, but benefit can also be derived from a low-cost home regimen (i.e. 50 week program for women, average age of 72, including leg exercises with rubber tubing, calisthenics, push-ups, and stair-climbing with a weighted backpack containing 10% of the subjects weight).


Benefits of resistance exercise

·       Increases bone density, muscle mass, muscle strength, muscle endurance, lean body mass, and enhances pain management (Exerc Sport Sci Rev. 1988. 16. 341).

·       Shown to maintain muscle mass and function as well as nutritional status in individuals with chronic renal insufficiency consuming a low protein diet (Ann Intern Med. 2001. 135. 965-976).

·       Shown to be cost effective for treatment of knee osteoarthritis, compared to aerobic exercise and education (Med Sci Sports Exerc. 2000. 32. 1534-1540).

·       Raises GH levels.


·       Hypertension – a systematic review and meta-analysis of 9 RCTs (n=223) of the effects of at least 4 weeks of isometric exercise on blood pressure in healthy adults concludes “Isometric resistance training lowers SBP, DBP, and mean arterial pressure. The magnitude of effect is larger than that previously reported in dynamic aerobic or resistance training” (Am J Cardiol. 2014. 89. 327-334).

·       Osteoporosis – improves bone density, increases muscle mass (so a fracture is less likely with a fall) and improves balance.


Flexibility exercise

·       Increases joint flexibility, decreases low back pain, enhances post-injury rehabilitation, and enhances pain management ((Phys Sports Med. 1989. 17. 203).

·       In general, lower cortisol and adrenalin levels.

·       Tai Chi (Alt Med Alert. 2007. 10. 88-91) See more information at the bottom of the web page ‘Complementary Modalities

o   Literally means “supreme ultimate power”

o   Historically was influenced by Chinese Taoism and Buddhism, and is believed to balance the flow of Qi within the body.

o   Five major styles of tai chi have developed.

o   All forms of tai chi involve meditation, breathing exercises, and slow, graceful movements.

o   Each session is composed of a series of specific postures combined into one long exercise.

o   Improves balance and muscle strength, based on a systematic analysis (Fam Pract. 2004. 21. 107-113).

o   Improves flexibility, balance, and fitness (as gauged by VO2 max). In a study of 19 sedentary elderly women, a 3 month program of short-style Tai Chi Chuan offers greater improvement in fitness than a brisk walking intervention (Age Ageing. 2006. 35. 388-393).

o   Reduces the risk of falling

§  Reduces the risk of falling in the elderly by 47.5%, based on a RCT in 200 subjects over age 70, in which treatment subjects met with an instructor twice a week for 20 minutes, and were encouraged to practice on their own for 15 minutes twice a day (J Am Geriatr Soc. 1996. 44. 489). This study in 2003 was named by the American Geriatric Society as the best research paper from the 1990’s, and was republished (J Am Geriatr Soc. 2003. 51. 1794-1803).

§  Reduces the risk of falling in the elderly, based on a RCT in 256 physically inactive subjects over age 70. The treatment group attended one hour classes 3 times a week for 6 months, and those in the tai chi group had 55% fewer falls (p=0.007). Repeat assessment 6 months after completion of the study showed that group differences with regard to falls persisted (p<0.001) [J Gerontol A Biol Sci Med Sci. 2005. 60. 187-194].

§  Lack of benefit seen with regard to reducing the risk of falling in two studies conducted in frail elderly in long term care facilities (J Am Geriatr Soc. 2001. 49. 859-865; J Adv Nurs. 2005. 51. 150-157).

·       Yoga

o   The sequence of stretches balances all parts of the body and has beneficial effects on the nervous system.  This is complementary to aerobic exercise and weight lifting because they increase blood supply to the muscles at the expense of the brain and many internal organs; yoga can increase the blood supply to the brain, skin, and various internal organs.

o   Yoga in combination with meditation and individual counseling regarding stress management in a 9 day outpatient program decreases TBARS, an indicator of oxidative stress (Indian J Physiol Pharmacol. 2005. 49. 358).

·       Martial arts:  emphasize agility, balance, and coordination.



·       Blair, Steven. Active Living Every Day. 2001. Contains evidence-based recommendations on exercise that bring behavioral strategies into the exercise arena.

·       Piscatella JC and Franklin B. Take a Load off Your Heart. 2003. Contains helpful tips on how to start exercising.

·       http://www.exerciseismedicine.org/physicians.htm – excellent printed educational material (for physicians) lower right portion of page


[Last Updated March 23, 2014] [Return to List of Topics]