Recently, there are many online workout videos that promise to "tone everything in 10 minutes".

These quick and easy workouts are popular among busy urbanites who want to burn fat and have a healthier body.

High-intensity interval training (HIIT) is a fitness programme with tailor-made, simple moves which involve intense bursts of high-intensity exercise followed by short periods of active rest with the aim of pushing the body to its limit and burning calories in a most effective way. Since HIIT raises total energy expenditure in a short period of time, it helps boost the afterburn effect so that the body keeps burning calories for 24 hours after exercise. As a result, HIIT is considered an ideal way to lose weight.

Dr Lobo Louie, Associate Professor of Department of Physical Education pointed out, "HIIT is an anaerobic exercise. According to the American College of Sports Medicine (ASCM), the afterburn effect initiated by HIIT can burn about 10% extra fat than aerobic exercises. However, quick exercises cannot burn a lot of calories so it cannot help with weight-loss plans. Indeed, the body only starts burning fat (beta oxidation) effectively after at least 30 minutes of exercise. Equally important is to follow a controlled diet."

Though HIIT is not a magic pill to lose weight, this simple and short workout is a good choice for urbanites to maintain long-term health. Dr Louie said, "Regular exercise benefits health. In addition to boosting cardio-pulmonary and metabolic functions, HIIT can also improve muscular strength and endurance, boost the immune system as well as reduce chronic diseases."

In order to prevent injury while exercising, Dr Louie reminded people to assess their body condition before starting HIIT and to do the workout step by step, "For beginners who may have weak muscles, improving exercise capacity should be the priority. This can be achieved by jogging for 20 minutes. This helps the body get ready for high-intensity exercises in four weeks. Another advice is the '10% rule', which means that the weekly mileage or exercise amount should be increased gradually by increments of 10%. Drinking enough water and scheduling HIIT workouts two hours before or after meals is crucial, as is sufficient rest after exercise to allow the body to recover.

Dr Louie stressed that the concept of HIIT is to get the heart and muscles to work at maximum capacity in short bursts. This may lead to cardiomegaly and increase the risk of recessive heart diseases. Should feelings of dizziness, chest tightness or shortness of breath appear during exercise, stop immediately and rest.