With HIIT, you never have to miss a workout because there’s no equipment needed – short bursts of intense activity can be done anywhere and be as effective as at the gym. Start your HIIT journey in the living room with bodyweight exercises, or head to the park or gym to use the cardio machines and free weights.
HIIT training – using a hard effort, even sprinting, with short recovery periods – isn’t for everyone, even though it can work on building endurance, slowly but surely, raising your effort and intensity over time.
Increased Cardiorespiratory Fitness
For instance, HIIT involves short periods of high-intensity exercise (running or sprinting, for example) alternated with recovery periods. Work phases last 30 seconds to a few minutes, depending on your level of fitness, and can be equated to 80-100 per cent of your maximum heart rate; recovery intervals tend to be shorter than work intervals as you get fitter.
That’s because HIIT instructs your body to burn fat for fuel at the same time as your muscles, by stimulating the production of muscle-building hormones such as adrenaline and noradrenaline to wake up fat burning receptors in muscles, which makes HIIT especially effective at whittling away belly fat and visceral fat tissue.
What’s more, HIIT workouts improve the muscles’ use of oxygen during exercise which reduces breathlessness and fatigue from chronic lung conditions such as chronic obstructive pulmonary disease (COPD). But HIIT is not for everyone: people with heart disease, diabetes or rheumatic diseases who are fit enough for exercise should stick with regular, longer aerobic training.
Lower Body Fat
HIIT workouts involve spurts of hard work that exceed what you’d get from lower intensity cardio exercise, so you burn more calories – helping you lose or maintain weight and reduce belly fat faster.
Your body then uses anaerobic pathways – chemical reactions that don’t require oxygen to run – in order to keep going through the short, intense work intervals you’re doing, which pumps up your calorie burn even after you finish exercising; this is called excess post-exercise oxygen consumption, or EPOC for short.
Research shows that you can work out for half the time with high intensity interval training (HIIT) and derive more cardiorespiratory fitness than with moderate intensity circuit training (MICT), which can already help you lose weight and reduce your risks for cardiovascular disease, diabetes, high blood pressure and high cholesterol.
For HIIT, he recommends getting started by first improving your baseline aerobic fitness with cardio before using HIIT on its own.
Increased Muscle Tone
HIIT workouts are often recommended for improved muscle definition and body composition. This is partly because of how aerobic and anaerobic benefits work together in these intense exercises, which are characterised by short bursts of ‘all-out’ exercise separated by brief rest periods. The result is a powerful combination that enhances muscle-building and fat-burning both for bodybuilders competing in natural or ‘pro’ divisions, as well as for individuals focusing on general fitness.
For instance, a good HIIT session doesn’t require a slideboard: you can do bodyweight exercises like jumping jacks or plyometric moves such as skaters or lunge jumps, or other simple drills like sprinting or rowing.
Navaretta recommends you start with at least three but ideally five bouts of HIIT every week, emphasising that you should start with small-yet-intense intervals and work your way up to longer bouts of higher intensity. Warm-ups and cool-downs should also be an integral part of every HIIT session, taking your heart and muscles from a resting state to an active state before and after exercise.
It’s been found that workouts that use high intensity interval training (HIIT) burn even more calories than slow every-day moderate intensity exercise and burn additional calories during the aftermath of exercise – as a result of a process identified as excess post-exercise oxygen consumption, EPOC, which allows your body to keep cranking up the calorie-burning heat even after your workout might seem finished.
Improved Mental Health
Like any exercise, HIIT can have potentially very positive effects on mental health, too. A 2022 study found that HIIT workouts were associated with ‘modest improvements in mental wellbeing and depression severity versus (1) long bouts of moderate-intensity cardio (eg, jogging) and (2) no exercise at all’.
HIIT training boosts the protein BDNF (brain-derived neurotrophic factor) that aids cell repair, regulates cognitive and emotional resilience – and is low in depression, bipolar, and schizophrenia.
To maximise the benefits of HIIT, workouts should be carried out safely and at a quick pace. A good five-minute warm-up before HIIT should include cardiovascular exercise (jump squats, skater hops or burpees) that you’re confident performing on a treadmill, whether this is a real treadmill or bodyweight exercises.
