To be healthy, you really do need to break into
a sweat when you exercise, say experts.
American College of Sports Medicine members
are concerned official advice to do 30 minutes of gentle exercise
each day is being misconstrued.
Some may take this to include a mere stroll
to the car, Circulation reports.
People should do at least 30 minutes of moderate
exercise five days a week, or 20 minutes of vigorous exercise,
like jogging, three days a week, they say.
There is confusion about what is the ideal
amount and intensity of exercise to improve health.
All agree that regular exercise is essential.
The World Health Organization has said 30 minutes of gentle
exercise each day could be enough to sustain a minimum level
of fitness.
Confusion
Recently, researchers at Queen's University,
Belfast, found walking for half an hour on just three days a
week gave similar fitness and blood pressure benefits to walking
for 30 minutes five times a week.
The sports scientists, however, say this advice
is misleading and could encourage people to do too little exercise.
"There are people who have not accepted, and
others who have misinterpreted, the original recommendation.
"Some people continue to believe that only
vigorous intensity activity will improve health while others
believe that the light activities of their daily lives are sufficient
to promote health," they told Circulation.
The authors include several experts who are
on a high-level committee in the US which next year will announce
America's new physical activity guidelines.
Their original recommendations in 1995 were
quickly adopted by the WHO and by the UK government in 1996.
They now stress that adults need to top up
their routine activities, such as casual walking and housework,
with structured exercise.
This should include vigorous (jogging) and
moderate aerobic exercise (a brisk walk), as well as twice-weekly
activities, such as weight training, which maintain or increase
muscular strength and endurance.
People can do short bouts of exercise to count
towards their weekly goals, but these must last for at least
10 minutes.
They say that even more exercise than this
may have further benefits. However, research has also shown
that too much exercise can be damaging to the body.
Indeed, the sports scientists say that some
people - including pregnant women and those aged 65 or older
- might be advised to do slightly less exercise and modify the
type of activities they do.
Professor Paul Gately, professor of exercise
and obesity at Leeds Metropolitan University, told The Guardian
that it was difficult to give "one-size-fits-all" advice.
"People who are very overweight would have
to do an hour of exercise a day just to maintain their weight
if they aren't going to change their diets," he said.
Dr David Haslam, of the National Obesity Forum,
questioned whether it was realistic to expect people to do two
weight training sessions each week.
"I'd rather see healthy habits built into daily
life - gyms aren't a sustainable habit for all," he said.
A spokesman for the Department of Health said
it was watching the developments but added there were no plans
to change current advice.
