Build your own
Build your own test that's specific to your health needs, choosing from our wide range of Biomarkers.
Choose from 30+ markers
5 mins read
Intensity is associated with how hard you work when exercising, or more precisely how hard your heart is working to pump blood around your body.
To put it simply high-intensity exercise is high impact, high activity for a short period of time. At this level of intensity, your heart is working at 80-95% of your maximum heart rate.
Low intensity exercise, however, is lower impact and lower aerobic activity. At low intensity, your heart is at around 40-50% of your maximum heart rate, but that doesn’t mean it isn’t effective, it just means you need to exercise for longer to achieve the maximum benefit.
View our Sports Tests and start your journey to better health today
When we talk about high intensity and low intensity exercise, we are essentially talking about anaerobic and aerobic exercise.
Anaerobic exercise is defined as any activity that breaks down the stores of glucose in the body for energy without using oxygen – anaerobic means ‘without oxygen’. These types of exercises are high intensity and short in length. They tend to boost metabolism as the focus is on building lean muscle, which will burn more calories.
Aerobic exercise is quite simply the opposite of anaerobic, the body uses oxygen – aerobic meaning ‘with oxygen’. Aerobic exercise requires the heart to pump oxygenated blood to working muscles. It is low intensity and longer in duration. Aerobic exercise helps to build up endurance by keeping the heart pumping for longer periods of time.
There are several types of high intensity exercises and include any form of workout that gets the heart rate up high and are performed in short bursts, these include:
Low intensity exercise is a lower impact form of exercise that puts less stress on your muscles and joints but still improves cardiovascular health, muscle strength and burns calories – just not as much as high intensity exercise. Examples of low intensity exercises include:
Whether you decide to do high or low intensity exercise or a mix of both depends on your goals and your overall state of health. Before you begin any new training regime, you should always consult your doctor for advice.
High intensity exercise is great for strengthening bones, building muscle, increasing metabolism, and increasing overall fitness and stamina.
However, it is not accessible to beginners as it requires a certain level of fitness to begin with. Due to the high intensity nature of the types of exercises, it can increase the risk of injury to joints and muscles.
Low intensity exercise can improve your levels of cholesterol, reduce blood pressure, improve your oxygen uptake known as VO2max [3], are easier on your joints, and are easily accessible to beginners.
However, to gain the benefits you need to exercise for longer periods of time and it’s less effective at building bone density.
If you’re usually fit and active, your exercise programme should incorporate high-and low-intensity activities. Low intensity exercise can be a great recovery day training method while high intensity exercise is a great way to burn calories and improve your cardiorespiratory fitness.
However, remember to take adequate rest after high intensity workouts as doing too much can result in injury. If you’re planning on incorporating some low intensity interval training (LIIT) into your routine, remember the trade-off for low intensity is time. So, if you usually spend 10 or 15 minutes on a HIIT workout, then you’ll probably need to make your LIIT workout last 20-30 minutes for it to be just as effective.
High intensity workouts particularly HIIT promise to overhaul our health and fitness. For many people the major advantage is they can be completed in relatively short periods of time but they’re not for everyone.
If you’re coming back from injury, have problems with your joints, or are a newbie to exercise, then low intensity exercise will be for you. However, if you’re usually fit and well and a bit of a fitness enthusiast, your exercise programme should contain a mix of high and low intensity exercise.
Low intensity exercise can offer benefits, especially on your rest days following high intensity exercise as it puts less pressure on your muscles and joints, reducing the risk of injury.
Patel, H et al. (2017). Aerobic vs Anaerobic Exercise Training Effects on the Cardiovascular System. World J Cardio: 9(2), pp 134-138.
Shiraev, T. (2012). Evidence Based Exercise. Clinical Benefits of High Intensity Interval Training. Australian Family Physician: 41(12).
Tanaka, H and Shindo, M. (1992). The Benefits of the Low Intensity Training. Ann Physiol Anthropol: 11(3), pp 365-8.
Thom works in NHS general practice and has a decade of experience working in both male and female elite sport. He has a background in exercise physiology and has published research into fatigue biomarkers.
Dr Thom Phillips
Head of Clinical Services
Like this article? Here are some more based on similar topics.