exercise benefit in elderly

​A systematic review/meta-analysis was recently published in the British Journal of Sports Medicine on the protective effects of even low amounts physical exercise in those >60yo (see exercise elderly brjsportsmed2015 in dropbox, or doi:10.1136/bjsports-2014-094306). Current recommendations are for 150 min of moderate-intensity or 75 min of vigorous-intensity physical activity/week, as measured by the metabolic equivalent task (MET, which describes the intensity of energy expenditure for specific activities) . For reference, resting energy expenditure is 1 MET,  moderate activity is 3-5.9 METs (eg brisk walking) and vigorous activity is >6 METs (eg, running). The MET-minute calculation is simply the sum of the #METs x #minutes x #days done/week for each of the activities. Studies suggest that there is substantial health benefits by performing 500-1000 MET-minutes/week (mortality benefit of 20-30%), the range suggested by the above recommendations. details:

--9 cohort studies included with 122,417 participants (60% women, mean age 72.9), and followed 9.8 years

--18122 deaths during follow-up period (14.8%)

--results:

                --low amounts of moderate-to-vigorous physical activity (MVPA), expending 1-499 MET-min/wk, was associated with a 22% reduction in mortality risk [RR=0.78 (0.71-0.87), p<0.0001], though there was a difference between men (a 14% reduction in morality risk  [RR=0.86 (0.80-0.94), p<0.001]), as compared to women (a 32% reduction [RR 0.68 (0.63-0.74 p<0.00001]) --all of these RR's are adjusted for age, sex, overweight, smoking, elevated BP, diabetes, plasma cholesterol, cardiovascular and chronic disease, cancer, depression, educational level and self-reported health

                --more extensive MVPA (expending 500-999 MET-min/wk), was associated with further mortality benefit of 28% in those following current recommendations of 150 min of moderate-intensity or 75 min of vigorous intensity physical activity/week) [RR=0.72 (0.656-0.80), p<0.0001]

                --even more extensive exercise (>1000 MET-min/wk) had a 35% reduction in mortality [RR=0.65 (0.61-0.70), p<0.0001]

                --of note, the relative benefit from the individual studies for each of the target exercises (low-dose, medium-dose and high-dose) were pretty consistent, even though the studies varied widely in participants (6 were from the US/2 from the Australia/one Asian).

                --the benefit was most dramatic in comparing those with low amounts of MVPA vs inactivity, with smaller incremental benefit as the amount of physical activity increased.

                --subgroup analysis found mortality benefit in cardiovascular disease was the most profound in those doing 1-499 MET min/week of MVPA (a 25% decrease in mortality), going up to 500-999 MET min/week (decreased mortality insignificantly improved to 26%), and going to >1000 MET min/week (a more impressive decrease of 40%). for cancer the relative numbers were 11%, 16% and 31%.

one concern is that 60% of older adults are not able to achieve the 150 min/week as recommended.​ so,

--this study reinforces that there is still significant  benefit to less-than-recommended exercise duration, both for men and women (though this is more impressive in women than men as noted above). by this meta-analysis, we should not be rigid in recommending the 150 min/week of exercise (since that really may be too much for some people and ultimately result in no exercise being done). so, the real clinical issue for us is to convince those >60yo to just do exercise, as much as they can reasonably do, recognizing that most of the benefit seems to be achieved even with small exercise duration. one issue for those of us in the northern climates is to plot a strategy with the patient to exercise in the colder months. i have had some success in suggesting walking up and down stairs for 10-15 minutes/day. there are a few studies also finding that even light intensity exercise (1.6-2.9 METs) has health benefits over being sedentary.

--an issue in a meta-analysis of observational studies is the question of reverse causation: is it that the healthier people tend to do more exercise, but the real increased longevity is because they are healthier, regardless of their doing exercise? the above meta-analysis did seem to control for chronic conditions and self-reported health status, making reverse causation less likely.

--so, given all of this, and as several recent blogs have reinforced, i do think that one of the most important things we do for patients, including the elderly, is to reinforce and help patients eat well and exercise, and the above study suggests that we try to negotiate a reasonable exercise program and not simply prescribe one that meets the recommendations....