5-10 min of exercise may improve health outcomes

Analysis of US  National Health surveys found that even a few minutes of leisure-time physical activity was found to have mortality benefits (see exercise low dose dec mortality BrJSportsMed2019 in dropbox, or doi:10.1136/bjsports-2018-099254).

Details:

-- 12 waves of the National Health Interview Surveys (1997-2008) were linked to the National Death Index records until 2012

-- 88,140 eligible participants aged 40-85 were included

-- 79% were 40-59 yrs old/22% >59yo, 47% men, 77% white/9% black/10% Hispanic, 14% less than high school education/30% high school/56% more than high school, 9% married, BMI 18.5-25 in 41%/25-30 in 39%/>30 in 19%, never smokers 53%/former smokers 25%/current smokers 23%, lifetime alcohol abstainers 20%/former drinkers 16%/light-to-moderate drinkers 60%/heavy drinkers 5%

-- after median follow-up of 9.0 yrs:

    --7855 all-cause deaths

    --1695 CVD-specific deaths

    --2269 cancer-specific deaths

Results:

-- all of analyses below were adjusted for sex, age, race/ethnicity. Further adjustments were done on education and marital status, BMI, smoking and alcohol intake. These adjustments did not show major differences from the numbers below.

-- 10-59 minutes per week of physical activity, vs no activity:

    -- all-cause mortality: 18% lower risk, HR 0.82 (0.72-0.95)

    -- CVD-specific mortality: nonsignificant 12% decrease, HR 0.88 (0.67-1.17)

    -- cancer-specific mortality: nonsignificant 14% decrease, HR 0.86 (0.66-1.11)

--150-299 minutes per week vs no activity:

    -- all-cause mortality: 31% decrease, HR 0.69 (0.63-0.75)

    -- CVD-specific mortality: 37% decrease, HR 0.63 (0.52- 0.78)

    -- cancer-specific mortality: 24% decrease, HR 0.76 (0.64- 0.89)

-->1500 min/week vs no activity:

    -- all-cause mortality: 46% decrease, HR 0.54 (0.45-0.64)

    -- CVD-specific mortality: 33% decrease, HR 0.67 (0.45-0.99)

    -- cancer-specific mortality: 87% decrease, HR 0.53 (0.39-0.73)

-- there were larger reductions in all-cause and cause-specific mortality for vigorous vs moderate intensity physical activity

    --in general, those doing light/moderate activity had a decreased all-cause death rate around 20-25%; CVD death about 15-30%, cancer about 10-20%

    --those doing vigorous activity of the same duration as those doing lighter activity had an additional 5-10% decrease in all-cause mortality, not much difference in CV deaths (with slightly higher rates in those doing vigorous activity in the 60-149 min and 300-599 minute groups), and 15-20% decrease in cancer deaths, but only in those doing at least 150 minutes/week

Commentary:

-- most guidelines suggest 150 min/week of moderate-intensity aerobic activity (eg brisk walking) or 75 min/week of vigorous-intensity activity (eg walking) in order to  decrease overall mortality, as well as cancer, diabetes and cardiovascular disease

-- the new 2018 guidelines from the US Dept of Health and Human Services/NIH/ CDC/etc (see exercise guidelines jama2018 indropbox, or doi:10.1001/jama.2018.14854) recommended:

    -- Adults should do at least 150 to 300 minutes a week of moderate-intensity, or 75 to 150 minutes a week of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous-intensity aerobic activity

    -- muscle-strengthening activities on 2 or more days a week

   -- older adults should do multicomponent physical activity that includes balance training as well as aerobic and muscle-strengthening activities

    -- pregnant and postpartum women should do at least 150 minutes of moderate-intensity aerobic activity a week

    -- moving more and sitting less will benefit nearly everyone

    -- individuals performing the least physical activity benefit most by even modest increases in moderate-to-vigorous physical activity

    -- additional benefits occur with more physical activity (of concern here was the finding in some studies that there might be harm in doing more than the suggested amounts of exercise). Both aerobic and muscle-strengthening physical activity are beneficial

-- the CDC noted in the National Health Interview Survey that in 2017 only about 24% of adults over 18yo met these guidelines, and this peaked in the 18-24 yr olds at about 33%, and decreased in the 25-64 yo to 25%, then in 65-74 yo to 16% and in those >74 yo to 8% (see https://public.tableau.com/views/FIGURE7_5/Dashboard7_5?:showVizHome=no&:embed=true )

-- this study does add or reinforce several potential important conclusions:

    -- even low levels of moderate physical activity seemed to have significant mortality benefit, including doing only 5 to 10 minutes per day

    -- very high levels of activity seemed to continue to increase important health benefits (contrary to some other reports finding that very high levels of activity were associated with higher mortality risk)

    -- for those able to do vigorous activity, benefits accrue at a lower time interval of exercise, thereby being more time-efficient

-- I did not include the specifics for those exercising 60-149 minutes, 300-449 min or 800-1499 min, but in general there was a dose-response curve.

-- as noted in other blogs on physical exercise (see below), physical activity provides many mechanisms by which health outcomes might improve, including: decreased inflammation, improved cardiac function, weight loss, changes in many hormones (cortisol, sex hormones), improved immunologic function, decreases in specific medical comorbidities such as diabetes/hypertension/hyperlipidemia…

-- advantages of the study include:

    -- its large number of people using a nationally representative sample of US adults

    -- they minimized the possibility of reverse causation (whereby those who were healthier were both likely to be able to do more exercise as well as live longer anyway) by excluding people who were followed within the 1^st three years of the study and who reported having at least one chronic disease condition

-- limitations of the study include:

    -- as a nationally representative sample, results may not be generalizable to medically high-risk patients

    -- the amount of exercise was self-reported, and the physical activity data was not available during the subsequent follow-up (i.e., the amount of exercise may have changed significantly during the course of the study, but was not incorporated in their analysis)

    -- very important other aspects of healthful behavior were not included, especially diet

    -- there was no information about the other cardiovascular and all-cause mortality risk factors (eg, blood pressure, lipids, diabetes…)

    -- this study only incorporated leisure time physical activity. People with more physically active jobs may well have important health benefits (though it is much harder to quantitate work-related activity), and it seems likely that the totality of physical activity is likely important. And even with similar jobs, those people who consistently take the stairs at work may have benefit those who always use the elevator, and these differences may be hard to measure accurately

So, the reason I bring up yet another study on the benefits of exercise is that some prior studies have had results suggesting that lower levels of exercise, especially in men, were not associated with significant benefit. This study suggests that even those doing 10-59 minutes/week (5-10 minutes/d) of light-to-moderate leisure-time physical activity seemed to derive mortality benefit. I think we clinicians can use these findings as a means to encourage and empower patients to start with even very small amounts of exercise, and hopefully over time and through motivational interviewing, help incorporate more exercise into patients’ lives…

--There are lots of prior blogs on the importance of exercise, including:

    -- for decreased mental health problems:  http://gmodestmedblogs.blogspot.com/2018/09/exercise-helps-mental-health.html

    -- for long-standing risk reduction in development of diabetes:  http://gmodestmedblogs.blogspot.com/2017/11/diabetes-lifestyle-changes-longer.html ; and http://gmodestmedblogs.blogspot.com/2015/03/exercise-and-development-of-diabetes.html 

    -- for decreased risk of stroke, even in those with the highest genetic risk: http://gmodestmedblogs.blogspot.com/2018/11/lifestyle-vs-genes-in-who-has-strokes.html

    -- improved quality of life for those with heart failure with reduced EF: http://gmodestmedblogs.blogspot.com/2016/09/vigorous-exercise-helps-those-with.html 

    -- decreased cancer risk: http://gmodestmedblogs.blogspot.com/2016/08/normal-bmiexercise-lower-cancer-risk-2.html 

    -- mortality benefit in the elderly: http://gmodestmedblogs.blogspot.com/2015/11/exercise-benefit-in-elderly.html 

    -- low level exercise improves memory: http://gmodestmedblogs.blogspot.com/2013/08/exercise-and-memory.html

    -- exercise was as good as drugs for mortality benefit in secondary prevention of CHD, rehab of stroke, treatment of heart failure, and prevention of diabetes: http://gmodestmedblogs.blogspot.com/2013/10/exercise-as-good-as-drugs.html

    -- etc etc

geoff​

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