High Intensity Training - IELTS Reading Answers & Explanations

You should spend about 20 minutes on Questions 13–27, which are based on Reading Passage 2 below.

High intensity training

Endurance vs intensity

The traditional view of exercise is that more is better. But now a new form of exercise is challenging the old view and causing debate between traditionalists and proponents of a new form of exercise, High Intensity Training (HIT). Current recommendations from the US Department of Health and Human Services say adults aged between 16 and 64 should take two kinds of exercise every week: aerobic and muscle-strengthening. Aerobic exercise covers activities that make you breathe harder and your heart beat faster – activities such as walking quickly, swimming or playing a relaxed game of tennis. Muscle-strengthening exercises work all the major muscle groups in a person’s body – legs, hips, back, chest, abdomen, shoulders and arms. The US Department of Health and Human Services recommends that adults do two hours and thirty minutes of moderate-intensity aerobic activity per week and muscle-strengthening activities on at least two days per week. A lot of people, perhaps understandably, never meet these targets, usually citing lack of time as the main reason.

However, a recent study has removed the old excuse. Professor Martin Gibala, from Canada’s McMaster University, has published research in the Journal of Physiology that shows doing less exercise can be more effective than time-consuming periods of aerobic and muscle-strengthening activities. High Intensity Training is very simple: it involves a warm-up period followed by a short burst of intense activity, usually 30 seconds to one minute, then a recovery period where you exercise at a gentler pace for a couple of minutes, then another short period of high-energy activity. After a second recovery phase, there is more energy-intensive exercise before slowing down for a while, then stopping. That’s all your exercise for the day. This cycle of warm up / intense activity / recovery / intense activity, etc can be applied to a variety of sports such as cycling, jogging and swimming.

How does it work?

There are a number of different explanations as to why HIT seems to be more effective than endurance exercise. Firstly, exercising at low intensity only burns calories while you are active so that the minute you stop, you also stop burning calories. In contrast, high-intensity exercise continues to work on your metabolism a long time after you have finished – and this can be up to 24 hours later – so that you continue burning calories for longer. Secondly, HIT builds your muscles, replacing fat with muscle mass. The third theory is that the sprint-and-recover cycle doesn’t give the body the chance to store energy in the same way as training over a long period: the body needs to use all the energy in one go rather than maintain the same energy level over a longer period and still being able to reserve some as fat. The final theory is HIT combines both aerobic and muscle-strengthening activities and uses many more muscles than regular exercise – up to 80% of the muscles in the body, compared with up to 40% for moderate jogging or cycling.

There have been numerous experiments into HIT. In one conducted by a team from the University of Colorado led by Kyle Sevits, five male volunteers were tested to measure the number of calories a typical HIT workout burns. The volunteers, aged between 25 and 31, were tested to make sure their hearts were healthy, and their body composition and resting metabolic rates were measured. The participants ate a specific diet, then taken to a hospital room where researchers were able to control the air intake and determine the oxygen, carbon dioxide and water content of the air. Through these indices researchers were able to measure how many calories the volunteers burned. While each person lived in the room, they were kept on their strict diet and could only watch TV or use a computer. However, on one day they were asked to participate in HIT on a gym bike, pedalling as fast as they could for five 30-second periods with four-minute recovery periods between. The results were startling: the volunteers burned an average of an extra 200 calories on the workout day in spite of doing high-intensity activity for just 2.5 minutes. Other experiments have revealed similar results. In Japan, a team from the National Institute of Fitness and Sport separated individuals into two groups. The first group trained five days a week over six weeks, taking an hour of moderate-intensity exercise per day, totally five hours per week. The oxygen intake of this group improved by an average of 9%. The second group’s training sessions were eight 20-second intense workouts followed by ten seconds of rest. Their oxygen intake improved by 15%.

Benefits to health

Good oxygen intake is a sign of a healthy adult but the workout routine has shown other health benefits in diabetes. Scientists at Herriot Watt University in Edinburgh found that short bursts of high-intensity activity every few days reduced the risk of contracting diabetes due to the beneficial effects on blood sugar. Similarly, a study in 2011 by Professor Gibala found that insulin sensitivity improved by 35% after just two weeks, which is important in enabling glucose digested from food to get to our cells and provide energy. Endurance is also increased: one study in 2006 found that eight weeks of doing high-intensity workouts meant subjects could exercise twice as long as they could before the study, while maintaining the same pace. Additionally, HIT increases the fat burnt and sustains more muscle. Finally, HIT stimulates production of human growth hormone (HGH) by up to 450% during the 24 hours after the workout has finished. HGH is not only responsible for increased calorie burning but also slows down the ageing process. It seems that HIT could keep us fitter and younger for longer.