Physical activities, including aerobic and muscle strengthening exercises, are recommended for all adults for improved health conditions and enhanced life span. A recent British Journal of Sports Medicine study investigated the relationship between weightlifting and all-cause mortality, especially death due to cardiovascular disease (CVD) and cancer. It further analyzed the health outcomes of an individual based on joint and independent associations with aerobic moderate to vigorous physical activity (MVPA).
Moderate to vigorous physical activity (MVPA)
An equal amount of both moderate and vigorous physical activity is commonly abbreviated as MVPA. Aerobic exercises are voluntary movements that enhance energy expenditure above baseline levels. All adults are recommended at least 150–300 minutes/week of moderate to intense aerobic physical activity or 75–150 minutes/week of vigorous-intensity aerobic activity by the Physical Activity Guidelines.
Muscle-strengthening exercises (MSE) improve or maintain muscle strength and stamina. Among MSEs, weightlifting via free weights or machines is one of the most common types with high recall validity. All adults are recommended to complete a minimum of two days per week of MSE for all major muscle groups.
Interestingly, according to the Behavioural Risk Factor Surveillance Survey, around 65% of Americans have successfully fulfilled the MVPA guidelines. The National Health Interview Survey reported that 28% of participants fulfilled MSE guidelines while 24% of participants followed both aerobic and MSE recommendations.
The majority of research has evaluated the health benefits associated with aerobic MVPA and not MSE. Very little evidence has been documented related to the health benefits of MSE. Among these, the majority have focused on a particular population or evaluated short-term outcomes instead of conducting large prospective observational studies with longer follow-ups.
About the study
The current study utilized data from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial conducted in 1993. Cox proportional hazard regressions were estimated to measure the hazard ratios and to determine the relationship between weightlifting and mortality after adjusting for lifestyle, demographics, and behavioral risk factors. A total of 99,713 adults were included in this study who had completed a follow-up questionnaire. This helped researchers understand how weightlifting impacted mortality.
It must be highlighted that weightlifting promotes lean body mass, which reduces mortality. Previous studies have indicated the muscle’s role in both endocrine and paracrine functions, which positively impacts human health. Weightlifting is also associated with improved musculoskeletal health and functional strength gains.
It was observed that both weightlifting and aerobic MVPA were independently associated with lower all-cause and CVD mortality. However, this was not the case for cancer, i.e., weightlifting and aerobic MVPA did not impact cancer mortality.
Interestingly, the association between weightlifting and all-cause mortality was stronger in females. Joint models revealed that individuals who fulfilled aerobic MVPA guidelines without any weightlifting showed 32% lower all-cause mortality. Individuals who only completed weightlifting 1-2 times/week without any aerobic MVPA exhibited 20% lower all-cause mortality. Interestingly, those following both MVPA and weightlifting were associated with a 41% lower all-cause mortality.
The findings of this study are consistent with previous studies that reported lower mortality with MSE. Scientists failed to evaluate the impact of duration of MSE on mortality because they are represented as session frequencies and not duration.
The current study has specifically focused on weightlifting; therefore, it has not fully captured the impact of all MSE on mortality. Generally, MSE also includes calisthenics, pilates, and plyometrics. In line with prior research, the present study documented the benefits of MSE (weightlifting) and aerobic activity in reducing mortality.
This study failed to establish causality and only enhanced the evidence base, owing to its single observational study design. It was based on a single-time assessment technique with time-varying behavior. Therefore, a serial measurement approach with a longer follow-up time must be undertaken in the future to capture the changes in behavior over time.
The authors failed to consider training load, training frequency, volume, i.e., number of sets and repetitions, and the duration of weightlifting undertaken by participants. The findings were not generalizable in terms of racial and ethnic groups because the cohort predominantly represented the non-Hispanic White population.
This study provided insights into the benefits of weightlifting for health status. It was emphasized that participants associated with weightlifting exhibited a lower mortality risk. However, those who followed a combination of weightlifting and aerobic MVPA gained more benefits than either type of exercise alone.