(NYTIMES) - Regular physical activity has many known health benefits, one of which is that it might help you live longer. But what is still being determined are the types and duration of exercise that offer the most protection.
In a new study published in the British Journal Of Sports Medicine, researchers found that although doing either aerobic exercise or strength training was associated with a lower risk of dying during the study's time frame, doing both regularly - one to three hours of aerobic exercise and one to two strength-training sessions a week - was associated with an even lower mortality risk.
Switching from a sedentary lifestyle to a workout schedule is comparable to "smoking versus not smoking", said data scientist Carver Coleman, one of the authors of the study.
The paper is the latest evidence in a trend showing the importance of strength training in longevity and overall health.
"The study is exciting because it does support having a mix of both aerobic and strength training," said Dr Kenneth Koncilja, a gerontologist at the Cleveland Clinic, who was not involved in the study. "That is definitely something I talk with my patients about all the time."
Cardio plus strength training offers the most protection
For the study, researchers used National Health Interview Survey data, which followed 416,420 American adults recruited between 1997 and 2014. Participants filled out questionnaires detailing the types of physical activity they had been doing, which included specifying how much moderate or vigorous exercise along with how many sessions of muscle-strengthening exercises they did in a week.
After adjusting for factors such as age, gender, income, education, marital status and whether they had chronic conditions such as diabetes, heart disease or cancer, researchers found that people who engaged in one hour of moderate to vigorous aerobic activity a week had a 15 per cent lower mortality risk. Mortality risk was 27 per cent lower for those who did three hours a week.
But those who also took part in one to two strength-training sessions a week had an even lower mortality risk - 40 per cent lower than those who did not exercise at all. This was roughly the difference between a non-smoker and someone with a half-a-pack-a-day habit.
Regular strength training is important for healthy ageing
Even though more research is needed, experts generally agree that regular strength training can have important benefits for healthy ageing, including maintaining a high quality of life.
"You will function at a much higher level for longer if you have good muscle strength," said Dr Bruce Moseley, an orthopaedic surgeon at Baylor College of Medicine in Houston.
Muscle strength is required for a number of daily activities, such as getting out of a chair, opening a jar of pickles, carrying groceries into the house or doing yardwork. However, "we progressively lose muscle mass as we age", said Ms Monica Ciolino, a physical therapist at Washington University in St Louis.
This muscle loss usually starts in a person's 30s and progresses with age. However, "we can absolutely fend off the negative effects" with regular strength training, she added. And it is never too late to start. Research shows that even septuagenarians with mobility issues can benefit from a regular strength-training programme.
Dr Moseley suggests aiming for a consistent strength-training schedule and easing into it to avoid overuse injuries.
"Keep it at a light and easy level at first," he said. "Once your body starts getting adjusted, then you can start increasing."
If you are still uncertain about certain exercises, he recommends seeking out expert advice through an exercise class or consulting with a personal trainer. The important thing, he added, is to get started and to make it a habit. Not only can this help you live longer, but it will also improve your quality of life.
"When I ask people, 'What does successful ageing mean to you', people say they want to be independent, they want to maintain their function and quality of life, they want to do the things that they want to do," Dr Koncilja said. "It's not necessarily just living as long as possible."