Consider these factors before doing a HIIT workout.
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Truth: The more energy you expend, the more calories you’ll burn. That’s the idea behind high-intensity interval training, also known as HIIT.
Over the years, HIIT has gained a reputation for being a quick and effective workout, appealing to all sorts of people: weight losers, bikini body hunters, strength builders, time-strapped workers, brides-to-be, novelty seekers, professional athletes… You can find HIIT workouts in Tabata, CrossFit, bootcamps and the trending Kayla Itsines Bikini Body Guide.
Spanning no more than 30 minutes, a HIIT session involves short, intense bursts of activity such as squat jumps, burpees and mountain climbers, with brief recovery periods in between. These moves, which require all-out, full-body effort, are meant to push your heart rate up to 100 per cent of the maximum. The rule of thumb is, if you can barely speak while executing those moves, you’re probably on the right track.
“HIIT pushes the body into the anaerobic threshold, the exercise intensity at which lactate starts building up in the blood stream, leading to muscle fatigue,” Dr Lim Ing Haan, an interventional cardiologist at Mount Elizabeth Hospital explains. “In doing so, HIIT improves exercise tolerance and fitness levels. With enough training, one can run or cycle up to twice as much as before. In other words, cardiovascular fitness is improved.
“Besides building a stronger heart, HIIT increases metabolism and speeds up calorie burn, at the same time preserving muscles,” Dr Lim adds.
Those benefits are certainly enticing, but HIIT is not for everyone. We get Dr Lim’s take on these commonly asked questions.
Is my heart suited for a high-intensity workout?
Those above age 35 should go for a basic health screening, which includes tests on blood pressure, cholesterol, diabetes as well as cardiac screening. For smokers and those with a family history of heart problems, I’d recommend a basic ECG (electrocardiogram) or a treadmill test before they embark on HIIT.
How do I know if I’m fit enough for HIIT?
As HIIT is physically demanding, you should at least be able to exercise for 20 to 30 minutes at 85 per cent of your maximum heart rate without any issues. Your maximum heart rate can be calculated by subtracting your age from 220. (If you’re 35, your maximum heart rate is 185.)
The best way to find out the intensity of your exercise is to wear a heart rate monitor. If your heart rate does not slow down during your resting interval, you’ll need to scale back on the intensity.
If you experience chest pain, breathing difficulties, nausea or giddiness during training, stop and cool down by walking. If those symptoms persist, seek medical help immediately.
How often should I be doing high-intensity workouts like HIIT?
Most programmes recommend thrice-weekly workouts, with periods of rest and recovery in between. Start with 10 to 15 minutes of HIIT, gradually increasing the duration to no more than 30 minutes.
Note that HIIT is not the only way to get a high-intensity workout. If you’re a runner, up the challenge by increasing your running speed and/or treadmill incline, or add dumbbells to your routine. The workout should put you at the brink of exhaustion, like these ones.
How can I push my physical limits without overexerting my heart?
It’s important to set realistic goals when it comes to exercise. If you’re new to exercise, it’s advisable to start slow and build up your speed and stamina progressively. Always listen to your body.
Also, establish your main reasons for exercise, whether they are to maintain your fitness level, lose weight, build muscles or achieve a sense of well-being. To build cardiovascular fitness, a moderate level of intensity where your heart rate is between 50 and 75 per cent (you’re able to talk in short sentences) is sufficient.