Is too much exercise doing you harm?

Monday, April 16, 2007
We all know that exercise is good for us but how much exercise do you do? Once a month, once a week, three hours a day? Or are you a "whenever you can kind of person"? But what about the people that spend hours sweating in the gym like they're addicted to exercise. Is that good for them or can too much exercise do you harm?

If you injure yourself it's obvious you're doing too much, but how do you set limits? That's what our reporter, Dr Andrew Rochford wants to find out.

The test

Andrew's meeting a couple of blokes who make him look like a sloth! These guys are hardcore distance runners and they're going to help him with a little experiment.

First up, all three of them need to have their blood taken to measure their white blood cell count. White blood cells are the frontline fighters against germs that invade our bodies. If there aren't enough of them on board, our immune system is compromised and it's open season for the bugs.

The theory is, too much exercise can reduce these precious white cells.

After the tests it's back to the track where Andrew and the boys are going to put the white blood cell theory to the test — by comparing their white blood cell count before and after a long, hard run.

Phil and Steve will be doing 25 kilometres while Andrew will finish up after about four-and-a-half kilometres.

When the boys finish their run it's back to the lab for another blood test to see if their white blood cells have gone up or down. Remember, the less white blood cells, the lower the immune system.


Twenty-four hours later, it's results time.

Phil's white blood cell count was at 1.32 before the race, then dropped to 0.84 one hour afterwards, before rising back up to 1.40 within 24 hours. That's a pretty good response and shows that his system was able to recover quickly.

Steve's count was 2.56 before the run but dropped to 1.44 immediately afterwards before bouncing back to 2.44 a day later.

Being super fit meant it was easy for their bodies to recover. But if the boys had done another 10 kilometres, or attempted a full marathon the next day, the drop in their white blood cell count would be far greater and they'd be more prone to getting sick.

As far as Andrew's results went, he scored a white blood count of 2.45 before the race, which dipped to 2.15 straight after and then soared back up to 2.50 a day later.

He may not be a top class athlete but this proves that four kilometres is well within his system's limits.

"If I'd tried the full catastrophe, the dip would have been much greater and the recovery would have been slower. Hence more chance of infection," Andrew says.

Could you be overtraining? Here are the warning signs:

  • Weight loss, muscle injuries and extreme fatigue are all signs that you're overdoing it.
  • Watch out for headaches, loss of appetite and insomnia too.

Ironically, research has shown that people who don't exercise much at all have something in common with people who work out a lot — the risk of infection.

It seems couch potatoes actually run a medium risk of getting sick while marathon runners, triathletes and other high-level athletes run a high risk.

For moderate types like Andrew, who like a bit of exercise but nothing too crazy, the risk of infection actually decreases, so the key to a healthy exercise regime is balance and moderation.

We're all told to get plenty of exercise, but when should you stop? We've just proven that too much exercise can actually be bad for your body. But what can it do to your mind? Can you really become an exercise junkie?

Adelaide-based sports psychologist, Dr Eugene Aidman has been studying athletes to find out how exercise affects the way they think and feel. In a recent trial involving 60 Victorian club runners, Dr Aidman sneakily deprived some of them of their daily fix, to see how it affected their mood.

"Not only the anger and the depression went up in the group that actually missed their schedule training, but also the fatigue," he found.

Going cold turkey on exercise can produce similar withdrawal symptoms to hard drugs. That's because intense exercise releases endorphins, our body's natural opiates, giving us so-called "natural highs".

Exercise junkies take their fitness routines to extremes — but what are the warning signs you've gone from a habit to an addiction?

Lets start with a few pointed questions:

  • Do you need longer, more intense work outs to get your daily hit?
  • Do you feel tired and irritated when you miss a session?
  • When you get a minor injury, do you keep training?
  • Are your work or relationship commitments starting to take second place to the gym?

If you said yes to any of those, it'd be a good idea to take a long hard look at your approach to exercise.

"People with obsessions tend to deny them. You ask any gym junkie whether they're obsessed with their exercise, they'll say no," says Dr Aidman.

Kelly Adams is a bodybuilder, but she doesn't think she's a gym junkie: "I just have a different lifestyle to some people. I work late afternoons, so for me to come in to the gym for an hour-and-a-half every morning is part of my timetable, you could say. It keeps me happy, it keeps the kids happy, I burn a lot of energy so that releases the good endorphins," she says. "I start off with ten minutes on the treadmill to warm up, I do three sets of 12 bicep curls, three sets of chin ups and three sets of chest press."

Kelly works out six days a week and believes she's got things in proportion but what do her family think?

"My husband's very supportive, well basically he has to be," says Kelly.

There is a fine line between getting it right and overdoing it. Here are some tips for balanced training:

  • If you work out a lot, make sure you're leaving enough recovery time for your system between intense bouts of exercise.
  • Slip a few low intensity workouts in between the really hard ones — alternate days for running and days for walking or light swimming.
  • Make sure to fuel up with a good combo of carbs, protein, and fat.


Yes, too much exercise can be bad for your health, in more ways than one, but that's no excuse not to do any at all. You need to keep your training sessions to a sensible length, try to build up your fitness slowly and listen to your body — it'll soon tell you when you've gone too far.

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