Weightlifting can almost halve older people’s risk of premature death, according to new research.
Muscle strengthening workouts protect against almost every life-threatening illness, the study found.
It makes the body leaner and can also improve mental wellbeing. Gyms are very sociable, another factor linked with a longer, healthier life, according to researchers.
The best results were seen in those who combined lifting weights with aerobic exercise and the associations were strongest in women.
Corresponding author Dr Jessica Gorzelitz, of the National Cancer Institute in Rockville, Maryland, said: “Our finding that mortality risk appeared to be lowest for those who participated in both types of exercise provides strong support for current recommendations to engage in both aerobic and muscle-strengthening activities.
“Older adults would probably benefit from adding weightlifting exercises to their physical activity routines.”
The findings are based on almost 100,000 over-50s in the US tracked for an average of almost a decade.
Weightlifting in the absence of aerobic MVPA (moderate and vigorous physical activity) lowered the risk of death by between 9 and 22 per cent, depending on the amount.
For example, one or two sessions a week was associated with a 14 per cent lower risk, reports the British Journal of Sports Medicine.
Similarly, aerobic MVPA on it own was associated with a 24 to 34 per cent lower risk of death from any cause, compared to peers who did neither.
But the lowest risk of death was seen among those who said they did both types of physical activity.
It fell between 41 and 47 per cent among those who met most recommended weekly levels of MVPA and who exercised with weights once or twice a week.
Educational attainment, smoking, BMI, race and ethnicity did not significantly change the associations observed, but gender did.
Dr Jessica Gorzelitz said: “Weightlifting and aerobic MVPA were both independently associated with lower all-cause and cardiovascular disease mortality.
“However, lower risk was not apparent for cancer mortality. Observed associations between weightlifting and all-cause mortality did not appear to vary by the participant factors we examined other than sex.
“We found statistical evidence the weightlifting-all-cause-mortality association was stronger in women.”
Several potential biological mechanisms could be behind the phenomenon, including weightlifting leading to more lean mass and improved body function.
Total lean mass is also independently associated with lower mortality risk, with studies examining muscle’s role in hormone function and how that can influence health.
Dr Gorzelitz said: “Finally, weightlifting, in particular, could be a socially related behaviour in that those who weightlift participate in social networks, assuming that this behaviour is done in a gym with others.
“However, it is important to acknowledge that consistent weightlifting is associated with other improvements, including functional strength gains and improved musculo-skeletal health.”
The study focused on weights, but there are other types of muscle strengthening exercise, said the researchers.
They cited callisthenics, which include push-ups and squats, pilates and plyometric exercises which include tuck jumps and burpees.
UK physical activity guidelines say muscle-strengthening activities include carrying heavy shopping bags, yoga, pilates, tai chi, lifting weights and working with resistance bands.
Others are doing exercises that use your own body weight such as push-ups and sit-ups, heavy gardening such as digging and shovelling, wheeling a wheelchair or lifting and carrying children.
Current guidelines on physical activity for all adults recommend at least 150 weekly minutes of moderate-intensity aerobic activity, or a minimum of 75 minutes of vigorous-intensity aerobic activity, or an equal combination of the two.
Dr Gorzelitz said: “In conclusion, participants who took part in weightlifting had a lower risk of mortality after accounting for aerobic MVPA.
“The combination of weightlifting and aerobic MVPA provided more benefit than either type of exercise alone.
“Our study provides support for weightlifting as a health behaviour associated with longevity for older adults at varying levels of aerobic MVPA participation.
“Importantly, these findings support meeting both the aerobic MVPA and muscle strengthening, including weightlifting, recommendations, especially targeting older adults who do not weightlift but may be currently aerobically active to maximise health and mortality outcomes.”
The US team drew on participants from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial.
It began in 1993 and includes 154,897 men and women aged 55 to 74 across the country.
In 2006, 104,002 of the participants were additionally asked if they had exercised with weights over the past year, and if so, how often they had done so, anything from less than once a month to several times a week.
And they were asked about the frequency and duration of both moderate and vigorous intensity physical activity over the past year.
Moderate intensity was described as “activity where you worked up a light sweat or increased your breathing and heart rate to moderately high levels” and vigorous activity as “activity strenuous enough to work up a sweat or increase your breathing and heart rate to very high levels”.
In all, the responses of 99,713 people were included in the final analysis, 28,477 of whom died over the study period.
Nearly one in four (23 per cent) respondents reported some weightlifting activity; 16 per cent said they exercised with weights regularly between one to six times a week.
Nearly one-third (32 per cent) were sufficiently aerobically active, either meeting (24 per cent) or exceeding (8 per cent) the guidelines on MVPA.