Human growth hormone, naturally produced, helps keep you lean and strong.
When you dig into the biology of why ageing makes human bodies look old, it's not hard to see why serious exercise is the nearest thing to a youth drug. The reason the body of a 60-year-old looks different from that of a 30-year-old isn't just the wrinkling of its outer casing, but what's happening to the stuffing inside - when muscle and bone start shrinking, bodies sag and posture droops.
The good news is there's an antidote: building muscle.
Not long ago, scientists thought that the gradual muscle loss that starts in the 40s was an inescapable effect of ageing that put you on the downhill run to frailty; trapped in a body increasingly made up of more fat and less muscle.
However, it's now known that strength training can reverse muscle and bone loss, making bodies work better and look leaner. Better still, it can help you produce more of the body's natural anti-ager, human growth hormone (HGH), according to strength coach Tony Boutagy, a lecturer with the exercise science department at the Australian Catholic University in Sydney.
In its manufactured form, HGH is controversial stuff. Touted as an anti-ageing drug and performance enhancer that helps reduce fat and boost muscle, it's reputedly one of the most stolen drugs in the world.
Your body's supplies of HGH, however, are produced by your pituitary gland. Production peaks in your mid-20s, then declines gradually with a sharper drop after the age of 50, Boutagy says.
"If you can increase production of HGH naturally with strength training, then there's less loss of muscle mass, better bone strength and less fat," he says.
When exercise stimulates a release of HGH, the hormone helps your body build more muscle tissue - and use up more of its fat. Exercise in general can stimulate HGH production - but strength training gives the biggest boost and the burn in your muscles when you lift a weight repeatedly is a sign you're producing HGH, he says.
To get an HGH spike takes more than a couple of bicep curls, however. Studies show that it takes about 50 minutes of strength training twice a week and it has to be fairly serious, Boutagy says. An example of a typical workout that could produce HGH would be a series of eight different strength training exercises targeting different muscle groups - lunges, squats or bicep curls are some examples - each one repeated until the muscle you're working feels exhausted
This is much less daunting than it sounds. For one thing, you're meant to rest for a minute between each set of exercises. For another, no one expects novices to work out at that level straight away.
As with anything else, you should build up to it, ideally under the guidance of a personal trainer or gym instructor. Such steps are a good investment in your body given the evidence that regular strength training helps maintain a healthy weight, strong bones and reduces your chances of needing a Zimmer frame down the track.
Louiza Menzel doesn't know how much HGH she's producing when she works out with weights, but it's bound to be more than that of most 44-year-old women. After training with Boutagy for six years she is strong enough to lift a 100-kilogram barbell, almost twice her body weight, off the floor in a move known as a deadlift.
"I do it to be fit and strong - and to have strong bones," says Menzel, who trains two or three times a week. Her small, curvy shape dispels any myths that strength training makes women bulky.
So can you skip the gym and buy an HGH supplement instead? HGH injections are prescribed at some anti-ageing clinics. However, its use as an anti-ageing supplement is prohibited, says Professor Ken Ho of Sydney's Garvan Institute.
"Anecdotally, we know it's prescribed, but anyone offering it is selling a myth. There's no evidence that it works and there are potential side effects: too much HGH can increase blood pressure and blood sugar levels," he says.
Despite the reputation of HGH supplements as a youth drug, performance enhancer and promoter of longevity, the evidence is less than glowing. A recent review of research into HGH's affect on longevity at Stanford University school of medicine found no evidence that it could help people live longer. There was some evidence it helped increase muscle and reduce fat but it did not improve bone strength and there was potential for side effects, such as joint swelling and diabetes.
Artificial supplements aside, Ho says any vigorous exercise will increase HGH naturally.
"Exercise has a lot of benefits - it helps you stay leaner and stronger and one player in that context is the production of HGH."
www.smh.com.au
