Mixing activities such as walking, running, and strength training may be linked to longer life, even when total exercise time stays the same, according to long-term cohort data.
Study: Physical activity types, variety, and mortality: results from two prospective cohort studies. Image Credit: New Africa / Shutterstock
In a recent study published in the journal BMJ Medicine, researchers used an extensive long-term dataset comprising more than 111,000 adults followed for three decades to investigate whether engaging in a wider variety of physical activities is associated with health benefits distinct from simply doing more exercise.
The study used data from two major prospective cohorts to examine mortality outcomes by exercise habits, finding that while total physical activity is strongly linked to reduced mortality, the diversity of that activity is independently associated with significantly lower risk, particularly among individuals who already met recommended activity levels.
Specifically, participants who engaged in the broadest range of activities demonstrated a 19% lower mortality risk than those with the least variety, a benefit that persisted even after adjusting for total energy expenditure.
Limitations of Volume-Focused Physical Activity Guidelines
Decades of research demonstrating the positive physiological benefits of physical activity have prompted public health guidelines to almost universally recommend 150 minutes of moderate activity per week as the standard for optimal human health.
Unfortunately, this approach focuses heavily on volume and intensity, with a growing body of evidence suggesting that this "one-size-fits-all" metric glosses over the complex physiological reality of human movement. For example, the biomechanical and metabolic adaptations to swimming are known to differ substantially from those to lifting weights or playing tennis.
Previous research has shown that aerobic exercise primarily increases maximum oxygen consumption (VO₂ max), while resistance training is superior for maintaining lean muscle mass and bone density. However, scientific data comparing the long-term longevity associations of specific activity types and the potential benefits of combining them has remained surprisingly sparse.
Study Design and Cohort Selection
The present study aims to address this knowledge gap and inform future public health policy by isolating the effects of physical activity variety from total volume. The study sample data were obtained from two robust long-term health studies, the Nurses' Health Study (NHS) and the Health Professionals Follow-Up Study (HPFS).
The study sample cohort included 70,725 women and 40,742 men who were free of chronic diseases like diabetes, cardiovascular disease (CVD), or cancer at the start of the study. The study notably included almost three decades of follow-up investigations (1986 to 2020) via validated biennial questionnaires.
Assessment of Physical Activity and Variety
Participants were required to report their average weekly time spent on various activities, including walking, jogging, running, bicycling, swimming, tennis/squash, calisthenics/rowing, and climbing stairs. This data was used to calculate the metabolic equivalent of task (MET) hours per week to standardize energy expenditure across different intensity levels.
Statistical analyses also calculated a physical activity variety score that tallied the number of different activities a participant consistently performed, with each activity counted only if it met prespecified thresholds (typically at least 20 minutes per week, or five flights per day for stair climbing), and cumulatively averaged over follow-up. Cox proportional hazards models were used to estimate mortality risks, adjusting for potential confounders such as diet quality, smoking status, alcohol intake, and family history of disease.
Mortality Outcomes and Activity-Specific Associations
Study findings revealed that more diverse physical activity patterns were associated with lower mortality than less varied patterns. Over the course of 2.4 million person-years of follow-up, 38,847 deaths were recorded across both sample cohorts. Total physical activity was inversely associated with mortality, with reductions in cardiovascular, cancer, and respiratory disease mortality largely plateauing at around 20 MET hours/week.
Notably, compared to those with the lowest engagement, participants in the highest categories of specific activities saw significant reductions in all-cause mortality:
- Walking: 17% reduction (Hazard Ratio, HR 0.83, 95% CI 0.80–0.85).
- Running: 13% reduction (HR 0.87, 95% CI 0.80–0.93).
- Tennis/Squash: 15% reduction (HR 0.85, 95% CI 0.80–0.89).
- Weight training: 13% reduction (HR 0.87, 95% CI 0.82–0.91).
- Swimming was observed as a notable outlier, showing no statistically significant reduction in all-cause mortality in the highest-volume group compared with the lowest (HR 1.01, 95% CI 0.97–1.05), a finding the authors note may reflect limited intensity information for this activity.
Independent Benefits of Physical Activity Variety
Most importantly, participants with the highest variety score (engaging in the most types of activities) had a 19% lower risk of all-cause mortality than those with the lowest variety score (HR 0.81, 95% CI 0.78–0.85, p for trend < 0.001). This benefit remained statistically significant after adjustment for total exercise volume, consistent with the possibility that, at similar overall activity levels, engaging in multiple activity types may be associated with lower mortality.
Interpretation, Strengths, and Limitations
The present study provides strong observational epidemiological evidence in support of more varied physical activity patterns. Its findings suggest that because different activities stimulate distinct physiological systems, such as neuromuscular adaptations from racquet sports versus cardiovascular adaptations from running, combining activity types may be associated with greater long-term survival.
While the study is limited by its reliance on self-reported data and a predominantly white cohort of health professionals, which limits generalisability, some activity types were not assessed consistently across all follow-up periods, activity intensity was not directly captured, and reverse causation cannot be fully excluded. Nonetheless, the data support the notion that a diverse physical regimen is associated with improved long-term survival.
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