Reducing the Risk for Death: Never Too Late to Exercise?

A previous study by Higueras-Fresnillo and colleagues, published in the April 2017 issue of the Journal of Geriatric Cardiology, analyzed this question.^[1]

Researchers established patterns of physical activity for a cohort of 2836 adults with a mean age of 71.3 years. These individuals were followed for a mean of 9.1 years for the principal study outcome of cardiovascular death.

Compared with chronically inactive adults, those adults who consistently exercised had a 58% reduction in risk for cardiovascular death. In addition, participants who increased their level of physical activity during follow-up had a 25% reduced risk for cardiovascular death. Participants who reported reduced physical activity during follow-up had similar levels of cardiovascular mortality as the persistently sedentary group.

The main study results were similar regardless of sex and body mass index, but there was evidence that physical activity was most effective for older adults with less chronic illness.

The current study takes an even broader view of how leisure-time physical activity (LTPA) affects mortality, with follow-up from adolescence into older age.

Study Synopsis and Perspective

Regular exercise reduces the risk for death even when started in middle age, according to a study that uses a life-course analysis to measure the link between mortality and LTPA. The results also show an association between LTPA and cause-specific mortality for the 2 leading causes of death: cardiovascular disease (CVD) and cancer.

Pedro F. Saint-Maurice, PhD, from the National Cancer Institute, Bethesda, Maryland, and colleagues report in an article published March 8 in JAMA Network Open that 2 to 7 hours/week of LTPA was associated with a 29% to 36% decreased risk for all-cause mortality, 32% to 43% risk for CVD-related mortality, and 14% to 16% decreased risk for cancer mortality compared with subjects with 1 hour/week or less of LTPA.

Remarkably, the risk reductions in subjects who had maintained high LTPA from adolescence were similar to those in subjects who only became active in midlife.

"We had anticipated that participants who maintained the highest levels of activity throughout adulthood would be at lowest risk and were thus surprised to find that increasing activity early or late in adulthood was associated with comparable benefits," the authors write.

"We specifically found that being inactive across early adulthood but increasing LTPA later at 40 to 61 years...was associated with 16% to 43% risk reduction in mortality," the authors write. "These mortality benefits were comparable to those associated with maintaining LTPA in all age groups from adolescence and into adulthood."

The researchers conducted a prospective cohort study using data from the National Institutes of Health-AARP (formerly American Association of Retired Persons) Diet and Health Study, established from 1995 to 1996. The analysis included 315,059 adult AARP members living in 6 states (California, Florida, Louisiana, New Jersey, North Carolina, Pennsylvania) or in 2 metropolitan areas (Atlanta, Georgia; Detroit, Michigan).

LPTA hours/week were self-reported at baseline for groups ages 15 to 18, 19 to 29, 35 to 39, and 40 to 61 years. Data were merged with National Death Index mortality records to determine underlying cause of death. Covariate analysis included age, sex, race/ethnicity, educational level, smoking status/dose, body mass index at age 18 years, total energy intake, diet percentage fat, red meat consumption, alcohol consumption, vegetable consumption, fruit consumption, and vitamin/mineral supplementation.

The researchers classified participants into 3 activity categories: maintainers (consistently high or stable LTPA over time), increasers (increased LPTA from adolescence or later in adulthood), and decreasers (active in early adulthood but less active thereafter).

With a mean follow-up of 13.6 years, 71,377 participants died from any cause, including 22,219 from CVD and 16,388 from cancer.

Risk for death was similar for those who maintained high LTPA throughout adulthood and those who increased activity in midlife (40-61 years of age). Specifically, relative to those who had 1 hour or less LTPA/week, the hazard ratios (HR) for those who maintained higher LTPA vs those who increased LTPA in midlife were 0.64 vs 0.65 for all-cause mortality, 0.58 vs 0.57 for CVD-related mortality, and 0.86 vs 0.84 for cancer-related mortality.

Study limitations included the following factors: the research was an observational study, and unmeasured confounding and reverse causality could not be ruled out, although the researchers adjusted their models for numerous risk factors.

"Increasing LTPA later in adulthood was associated with mortality benefits that were similar to those associated with maintaining higher levels of LTPA across the adult life course," the authors conclude. "Our findings suggest that it is not too late for adults to become active. These findings are particularly informative for health care professionals advising individuals who have been physically inactive throughout much of their adulthood that substantial health benefits can still be gained by improving their physical activity habits."

The authors have disclosed no relevant financial relationships.

JAMA Netw Open. Published online March 8, 2019.

Clinical Implications

• A previous study found that increasing physical activity levels among older adults was associated with a reduction in the risk for cardiovascular mortality, especially among individuals with less chronic illness. A reduction in physical activity among older adults was associated with similar rates of cardiovascular death compared with individuals with persistently low levels of activity.
• The current study demonstrates that persistent LTPA through middle age into older age can reduce all-cause, cardiovascular, and cancer mortality, as can increasing LTPA even in older age. However, reducing LTPA during adulthood is associated with a risk for mortality similar to that of individuals with persistently low LTPA.
• Implications for the Healthcare Team: The current study should be encouraging that it is not too late to gain significant benefits from LTPA in older age.