Everyone knows that exercising is beneficial to health. But how much exercise is considered enough? How long should each of your workouts last before you can start reaping the health benefits?

“To answer these questions, we can turn to exercise guidelines set by the World Health Organization (WHO) for general health purposes”, says Ms Cindy Ng Li Whye, Principal Physiotherapist at the Department of Physiotherapy and LIFE Centre, Singapore General Hospital (SGH), a member of the SingHealth group.

Based on a wealth of research, the WHO has set four basic exercise guidelines for adults aged 18 to 64:

1. Adults should target to do at least 150 minutes of moderate-intensity aerobic physical activity a week.
2. If the intensity of the aerobic exercise is vigorous, the duration can be halved (75 minutes).
3. Total exercise time can be split in 10-minute increments.
4. In addition to 150 minutes of moderate exercise per week, muscle-strengthening exercises should also be performed at least twice a week.

Muscle-strengthening exercises can also be referred to as “resistance training”. The resistance can come from workout machines, free weights or barbells, elastic bands, water or even your own body weight (e.g. push-ups).

While light exercise feels effortless, moderate-intensity exercise provides a slight challenge. During moderate-intensity exercise, your breathing quickens and you break into a sweat after about 10 minutes of working out (in a climate-controlled environment). And even though you have little or no difficulty chatting while exercising, you definitely have insufficient breath to sing.

For vigorous-intensity exercises, you will find that breathing is deep and rapid, and perspiration takes place within just minutes. You also won’t be able to say more than a few words before having to pause to catch your breath.

“The best way to know if an exercise routine is suited for you is to listen to your body. If you run out of brea​th quickly or begin to experience pain, then perhaps it is too intense for your fitness level. Slow down a bit and gradually increase the intensity,” Ms Ng advises.

"Individuals should exercise at a moderate intensity, corresponding to the level 3, and up to 5, on the'Rate of Perceived Exertion'; below," she says.

If you lack time…

Combine your aerobic and resistance training into a single session using circuit training. Circuit training is where you move from one training station to the next with minimal rest intervals.

If you want to lose weight…

For optimal weight loss, you would need to go beyond the 150 minutes of moderate-intensity exercise per week. These exercise guidelines are meant for health maintenance and general disease prevention. When it comes to losing weight, experts recommend targeting 250 minutes of such moderate-intensity exercise.

If you want to break the monotony of exercise…

For fitter individuals who are bored with doing the same exercise routine, high-impact interval training (HIIT) serves as a great alternative. In addition to increasing heart rates for improved fitness, it can also burn more calories within a shorter time.

If it was some time since you last exercised...

As you haven’t exercised in a while, it is advisable to get clearance from your doctor before embarking on an exercise programme. And if you have never done any resistance training and have musculoskeletal issues (such as back pain and knee pain), please consult a physiotherapist to get an individualised exercise programme.

The LIFE Centre at Singapore General Hospital (SGH) has a multidisciplinary team of experts who can provide you with guidance on weight management, exercise and diet.

Ref: S13