What exercises are good for osteoporosis?

We put this question to Dr Chris Smith...

Chris - It's interesting that Carolin has been talking about space because of course, one of the big risks of going into space and experiencing microgravity or weightlessness, is that you don't have any loading of your bones and astronauts come home with a bone age, equivalent to someone in their 70s and 80s, unless they do something about it. Because we have evolved to live on earth and experience the shocks that gravity throw at us - every time you get out of bed, every time you stand up from a chair, when you step off a curve, when you get in and out of the bath - you are applying a lot of stress vertically along your bones. And your bones have various chemical receptors in them that can detect that stress. In response to that stress, they secrete various factors that trigger the bone to grow more. In this way, the more loading you have on your bones, the more you do, the more dense your bones are going to be. Now, the reason that Linda is interested in osteoporosis I suspect as she's female is that women are at a disadvantage over men because the other thing that makes bones stay strong is the male and female hormones but women rely on oestrogen to keep their bones strong. And once you go beyond the age of the menopause - about age 50 - when the ovaries run out of eggs and you stop producing anymore eggs and therefore, you reduce your oestrogen level, your bones are at greater risk of thinning. And that's why people are advised to take regular load bearing exercise. Not to the extent that you damage your joints or damage your bones by severe exercise, but enough to initiate this stimulus to grow. And this should keep your bones strong. So, very, very severe exercise is not so good, non-load-bearing exercise like swimming is less good, but regular walking is pretty good especially if you're at risk of getting symptoms like osteoporosis.

Kat - I know I'm a big fan of weightlifting. I did hear that weightlifting was actually quite good and I think women are very reluctant to even lift any weights at all.

Chris - Anything that transfers more load through your skeleton is a good thing, but equally, it's important to do things that are within your limits. In fact, there's been a friend of ours who's been on this programme a number of times, Ken Pool who I met at Addenbrooke's Hospital the other day and he's now got a bone scanning technique where they can get their patients to hop on one leg a number of times a day and they can see the bone on the hopped leg getting denser just where they've hopped. You can then get them to do a prescribed amount of exercise which can include hopping because it's great low-bearing exercise and you boost the bone density. He just has published that.