Should you prioritise strength training or cardio as you age? I asked a metabolic health expert

If you’re on social media, over 40 and so much as glanced at a post about fitness, I’ll bet the algorithm has hammered home the message that you should be strength training.

Credit where it’s due, for once social media is spreading great advice, given that muscle mass naturally declines as you get older and resistance training is the only way to combat this.

But with the limelight so squarely on lifting weights, cardio isn’t getting the attention it deserves.

Amanda Lim—a former athlete, personal trainer and founder of preventative health medical clinic liftCLINIC—agrees both strength training and cardio training are essential components of an exercise program that prioritises longevity.

“There isn't really a way to pick one or the other if you want to maximize your potential health outcomes in the future,” Lim says. “You can’t deny the impact of heart health, but you also want to be able to stand up out of your wheelchair.”

I asked her to explain why each is important and how to measure it, so you can identify where you’re weaker and prioritise that, plus how to get started.

Why is strength training important for longevity?

According to Lim, strength training can improve your overall longevity for two reasons: it can increase your lifespan and your ability to do day-to-day tasks.

“In the clinic, we measure hand grip strength through using a dynamometer, and our hand grip strength measurement is a proxy for muscular function,” she says, adding: “We know that for every 5kg reduction in hand grip strength in the force that you can apply, there is a 16% increase in your chance of dying from anything.”

As well as increasing your lifespan, strength training can increase your healthspan—the number of years you live in good health.

“Progressive overload strength training through the six functional patterns, which are squat, hinge, push, pull, rotate, and carry, is the best way to develop that type of strength that then translates into these longevity outcomes,” Lim explains.

Each of these movement patterns reflects movements you do in everyday life. Practising these movements with weights helps you maintain the capability to do these movements as you age.

“The ability to take care of ourselves, like being able to get off the toilet by yourself, take a bath by yourself, change your clothes, those things are correlated with your healthspan [...] and that is where the strength training comes in,” Lim says.

Why is aerobic exercise important for longevity?

According to Lim, it’s great that more people are acknowledging the importance of strength training, but that shouldn’t undermine the value of cardio fitness. “We must remember that heart disease is the number one killer of men and women,” she says. “We can’t get so narrow in the focus on muscles and strength and function that we forget about the primary story, which is the heart.”

With this in mind, cardiovascular fitness is crucial to longevity. A good way to measure your cardiovascular health is your VO2 max, which refers to the maximum amount of oxygen your body can use per minute during intense exercise.

“There is a level of intensity that’s demanded in order to increase your VO2 max,” Lim says. “The good news is that intensity is relative to your current fitness levels, so you don’t need to necessarily start off running sprints. It could simply mean that you need to pedal the bike a little bit faster.”

“Plus, with that very intense style of exercise, the dose is smaller. So those fitness gains take more intensity but less duration,” Lim explains. If you want to make sure you’re doing enough, Lim recommends tracking your heart rate on a wearable device like a Fitbit or Apple Watch and trying to make sure that you get up to at least 80% of your maximum heart rate for 10 to 15 minutes.

Lim references a study published in the Journal of the American College of Cardiology which followed over 750,000 U.S. veterans. Researchers found that those in the least fit group had a fourfold increase in all-cause mortality compared with the most fit.

That means that if you want to improve your chances of a longer lifespan, working on your cardio fitness can make a notable difference.

How to combine strength and cardio training

For exercise newbies, Lim recommends putting two hours aside each week for movement and dedicating one to strength training and one to cardio.

“Do an hour of each or split that into four sessions of 30 minutes,” she suggests.

You can use various forms of resistance during your strength training workout: your bodyweight, resistance bands, dumbbells or machines.

For your cardio, do anything that raises your heart rate. However, Lim caveats this by saying: “If you’re doing an hour of cardio, make sure at least 10 of those minutes are difficult [...] The rest of your workout can be in that low to moderate aerobic zone.”