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Greg Whyte OBE

Physical Activity Expert


11 November 2017Why too much exercise could be bad for you

Is going to the gym for an hour every day part of your routine? Maybe you are training every evening for a marathon, or cycling 30 miles every weekend on your high-tech bike. Either way, if you are among the growing numbers of superfit adults, you may be damaging your health.

New research suggests that what might seem a like a commendable fitness routine can be harmful. Scientists have found that people who work out for more than seven and a half hours a week could be at higher risk of heart disease.

“High levels of exercise over time may cause stress on the arteries, leading to higher coronary plaque build-up,” says Dr Jamal Rana, a cardiologist at Kaiser Permanente in northern California and a lead author of a new study published in the latest issue of the American science journal Mayo Clinic Proceedings. Rana joined researchers from the University of Illinois to track the physical activity of more than 3,175 people for 25 years, asking them to report on their exercise levels eight times during that period.

He found that people who did seven and a half hours of moderate-intensity activity a week, including cycling or brisk walking, were 27 per cent more likely to have a build-up of coronary artery plaque than those who did the recommended minimum of 150 minutes a week. White males were particularly at risk, with an 86 per cent higher chance of calcification.

Most volunteers were aged 18 to 30 when the trial began and in middle age (43 to 55) when it ended. CT scans assessed the build-up of calcium — a predictor of heart disease — on their artery walls.

While we should remember that the research tracked people for 25 years, and looked at those who maintained extreme levels of fitness for a sustained amount of time, it’s also true that the research is not the first study to raise questions about the effects of extreme exercise. A number of studies have found that some long-term endurance athletes may be at a heightened risk of abnormal heartbeats, scarring of the heart tissue and other unwanted changes in the structure of the heart muscle. In a paper for the British Journal of Sports Medicine in 2012, Greg Whyte, a professor of applied sport and exercise science at Liverpool John Moores University, found that intensive endurance training triggered changes in blood markers that may make some people more susceptible to a heart attack. “We are talking long-term high mileage over many decades,” Whyte says. “Most people need to do more than the minimum recommendations for improved fitness.”

So, how much exercise should we be doing? “As with most things in life, moderation is good,” Rana says. His study suggests that as little as 75 minutes a week — a little more than ten minutes a day — of the kind of vigorous aerobic exercise most people attempt at the gym, or 21 minutes a day of more moderate exercise, such as power-walking, yoga or Pilates, is enough to stay healthy. For optimum fitness — to work our bodies more than the amount needed to stay healthy, yet not so much that we harm ourselves — we should aim for three and a half hours a week (30 minutes every day) of workouts that raise our heart rate and load our muscles.

Matt Roberts, the personal trainer, says that we should all address what he calls the FIT factors — frequency, intensity and time — as we age. “You should be aiming to exercise or be active on four or five days each week,” he says. “This is not set in stone and you can do less, but it will take you longer to reach your goals.”

He recommends making one of your weekly workouts an interval session. “That’s an all-out effort for as little as 15 seconds followed by a timed recovery and repeated five to six times.” High-intensity interval training (HIIT) can help to keep your metabolism primed (it can fall by as much as 25 per cent in middle age). Research at Abertay University in Dundee suggested that, on average, overweight men lost 1kg of fat in two months by sprinting flat-out for 60 seconds twice a week on an indoor bike. Dr Peter Herbert, a physiologist at the University of Wales Trinity Saint David, last year showed that six weeks of HIIT improved blood pressure, heart-rate readings and recovery in a group of volunteers aged 50-plus.

You really don’t have to overdo it, especially when you reach your forties — which is the time that a lot of people start panicking about their middle-age spread and start hitting the gym hard. At this age you should avoid repeated, excessively long aerobic workouts, says another personal trainer, Dalton Wong. He recommends no more than 45 minutes of aerobic exercise a few times a week. “More than that might raise levels of the stress hormone cortisol that exacerbates ageing,” he says.

A study in the American Journal of Preventive Medicine suggests that simply doing more brisk walking from your twenties through to your middle years can improve your lifespan. Alpa Patel, an epidemiologist with the American Cancer Society who led a trial involving nearly 140,000 people, found that walkers had a 20 per cent reduced risk of premature death compared with those who walked less. The results of his 13-year study also found that walkers who did no other form of exercise gained almost as many health benefits as those who did other workouts.

Aged 20-35
Aim for 3½ hours of exercise a week

The NHS recommends 150 minutes of exercise a week, which will keep you in reasonable shape, but for optimum fitness aim for three and a half hours. Your regimen could include: weight training to build muscle mass; yoga or Pilates for flexibility; moderate cardiovascular exercise, such as brisk walking, running or cycling; and one challenging class such as spinning. Do at least an hour and a half of moderate cardiovascular exercise (in two sessions).

Lift weights twice a week

It pays to take weight training more seriously because it will help to combat the natural loss of muscle mass with age. It will also help to protect bones long-term. Bone mass deteriorates sharply in women of menopausal age, and declines in men at about the same time. Don’t forget flexibility — yoga will help to prevent future mobility issues. To be superfit without risking your health, you could exercise for three and a half hours a week.

Take up interval training

Boost the natural slowing of your metabolism by adding some shorter, high-intensity interval training, or HIIT, to your regimen. This kind of workout is also kinder to vulnerable knees and tendons than longer runs. Make sure that you work on your flexibility with some yoga or Pilates. Three hours of exercise a week is more than enough — it’s a good idea to include a couple of short weights sessions.

Do at least 30 minutes of yoga a week

To be in great shape at this age, try to do a few half-hour sessions a week of cycling or swimming. Dancing is also a very good aerobic activity. Muscle mass is vital for strength and posture, so lift weights or do some resistance work every week, even if it is just a short session of squats and leg raises. Also include a session of yoga or Pilates.

Source: https://www.thetimes.co.uk/article/why-too-much-exercise-could-be-bad-for-you-j5758l22f