Australasian Science: Australia's authority on science since 1938

Death on the Instalment Plan

By Tim Olds

How much does watching TV, having a beer or walking to work alter your life expectancy?

Did you watch telly last night? If you’re like most Australian adults, you would have spent a couple of hours in front of the box. Well, you can knock 44 minutes off your life. That’s right, every time you sit down to a couple of hours of The X-Factor or Downton Abbey it means that you will die 44 minutes earlier than you would have otherwise.

Maybe you had a couple of beers as you watched the cricket? That’s OK, but the third one will cost you 30 minutes of life, the same as a Big Mac. Each cigarette costs you 15 minutes, let alone the time it takes to smoke it.

Not much is certain in this world, but there is one thing we can be quite sure of: how you use your time affects your health. At the University of South Australia, the Health and Use of Time (HUT) Group has been exploring the links between how we use our time and our health.

It’s not just physical activity and TV. Sleep, social interactions and cognitive behaviours can have huge impacts on our physical and psychological health. Learning to play a musical instrument or learning a foreign language as a child – even if you give it up later – greatly reduces your risk of developing Alzheimers.

Even where we do things matters. In the celebrated “windows” study, hospital patients randomly allocated a room with a window looking out onto a wooded area used fewer drugs and spent less time in hospital than those without windows.

So is there any good news? There certainly is. Eating the recommended amount of fruit and vegetables each day adds half an hour to your life, and every hour of exercise increases your life by 1.5 hours.

But be careful – the psychological benefits of exercise depend on when and where you get your physical activity. A University of Queensland study found that leisure-time physical activity does wonders for psychological well-being, but if we get our physical activity from active transport (walking to work, for example) or at work then we get no – or even negative – psychological benefits. A large Norwegian study found pretty much the same.

Maybe it has to do with how much we enjoy different activities. One of our recent studies in the HUT Group asked 109 adults to recall everything they did over a 24-hour period and to rate how much they enjoyed each activity on a scale of 0 (hated it) to 10 (absolutely loved it). It may surprise some readers to know that sex came out on top, with a rating of 9.5. Sleep (7.5) and video games (8.3) also did well. At the bottom of the list? Work (6.6), walking (6.3), driving (6.1) and chores (5.9).

Then of course there are the things we can’t do much about. Being female adds about 1.5 hours to your life every day, being an Australian rather than a Russian adult male gets you an extra 10 hours/day (all that vodka), and living today rather than 100 years ago is worth 7.5 hours/day for adults.

So the choice is yours. By all means crash in front of Top Gear, have that extra beer and a burger. Have a cigarette while you’re at it. That’s 90 minutes off your life. Or you can have your fruit and veg and go jogging for an hour. That’s 2 hours extra on your life.

The choice is yours. You may not like it now, but when you’re on your death bed you’ll value those extra hours.

Professor Tim Olds leads the Health and Use of Time Group at the Sansom Institute for Health Research, University of South Australia.