What happens to your fitness as you age – and what you can do about it

"The best thing to do [for longevity] is to maintain lifelong exercise," says Graeme Close, professor of human physiology at Liverpool John Moores University. Photo / Anupam Mahapatra, Unsplash

It's common to feel some aches and pains as we get older, but the announcement last month that England all-rounder Ben Stokes has quit ODI cricket because, at 31, he feels his body is "letting me down", shows that the decline might start sooner than we think.

Stokes blames his punishing schedule, but many less active people can start to notice a change from their 30s onwards.

"Data suggest that between the ages of 30 to 40 we start to lose muscle mass, both the number of fibres we have and the size of the fibres," says Graeme Close, professor of human physiology at Liverpool John Moores University.

"If you think of muscle as bundles of straws tightly packed together, we lose both the number of straws and the remaining ones get smaller, but with the right diet and training we can still be amazing."

After the age of 20, our basal metabolism rate (the number of calories your body burns when resting) drops by 1 to 2 per cent every decade, while muscles start to shrink at the rate of 3-8 per cent each decade. Now is the time to establish a solid fitness regime. "The best thing to do [for longevity] is to maintain lifelong exercise," says Professor Close. So how can we maintain our fitness with each advancing decade?

In your 30s

Make sure you're doing regular cardio sessions and strength training, using body weight exercises and progressing to weights under supervision. Pilates can help women repair their core, including the pelvic floor, after childbirth.

DO IT: Three sessions of cardio a week, plus one to two sessions of strength work and Pilates once or twice a week for postnatal women.

In your 40s

"If you aren't doing HIIT training [high intensity interval training] now is the time to add it in," says Hollie Grant, personal trainer and founder of PilatesPT.

Research from Liverpool John Moores University found that 60 seconds of high-energy cardio, such as push ups or star jumps, followed by 60 seconds of low intensity, such as marching on the spot, improved cardiovascular fitness the most. It has also been shown to reduce the risk of diabetes, as well as reducing the fat around our internal organs which can increase your risk of some cancers and coronary heart disease. But, Grant warns, "you may find it takes you longer to recover in your 30s, so leave adequate rest time (around 48 hours) between sessions." He also advises strength training to help halt the decline of muscle mass.

DO IT: Three weekly HIIT sessions, plus up to two strength sessions.

In your 50s

The average age for women to go through the menopause is 51. "The change in estrogen levels during the menopause can result in insulin resistance, leading to an increase in belly fat," says personal trainer Zana Morris.

She recommends keeping up the HIIT, but for those with joint problems, walking might be the answer: a US study found that middle-aged women lost an average of 17 pounds (7.7 kilograms) after six months of brisk daily walking (swimming, the study found, did not reduce body fat). Grant also recommends adding yoga or Pilates to improve flexibility and balance.

DO IT: Daily walking at a brisk speed for an hour, one to two weights sessions (body weight or with dumbbells) and Pilates or yoga once a week.

In your 60s

Women are at higher risk of developing osteoporosis because of rapid loss of bone density during and after menopause. Walking can help increase bone density: a study by Tufts University, Boston, found that women who walked more than 7.5 miles (12km) per week had higher bone density than women who walked less than 1 mile per week.

Morris says that weight training, as well as increasing muscle generally, can target aches and pains. "Training back muscles will help keep shoulder and neck issues at bay, while strong glutes and hamstrings are vital for healthy, supple knees and hips."

DO IT: Walk at least a mile a day, plus two weight training sessions.

In your 70s

It's not the time to stop. "If you have been active throughout adulthood you should be able to continue with daily exercise throughout your 70s," says Grant.

Eddie Brocklesby is testament to this; she became the oldest British woman to compete in an Ironman Triathlon at the age of 72. And strength training is more important than ever. German researchers found that three sessions a week, consisting of three to four sets with about 10 repetitions per muscle, builds muscle mass. Listen to your body – prioritise flexibility and balance work.

DO IT: Three sessions of strength training, plus one to two tai chi or Pilates classes a week.