Written by Dr Ray SH Ng (General Practitioner with interest in Sports and Exercise Medicine)
Whilst more of us are working from home or unable to access the gym, I have been thinking about what is the best way for our patients and the wider community in Hong Kong to stay physically active. There are plenty of sources telling you what type of exercises you should be doing and I will explain what is the scientific basis behind this and what you are trying to achieve with all the effort you are putting in.
This week, I will talk about what you can do as a Beginner if you have not done much exercise (i.e. not worked out properly for the past 2 months and may be deconditioned).
This is in the form of High Intensity Interval Training (HIIT) which builds up your muscle capacity or skeletal fibers through a combination of both aerobic (requiring oxygen) and anaerobic (without oxygen) metabolism.
It is important to do activities that you enjoy so you can maintain motivation. Remember it is not duration that is important but the frequency and consistency.
So exercising intensely 15 mins per day for 5 days per week is more effective than doing 60 mins on a Sunday for instance.
Most of the activities mentioned here are not new but they should serve as the core exercise for anyone who wants to stay fit. Your main objectives are:
This involves working on the largest muscles in the body:
To put into simplistic terms, the first two minutes of intense exercise involves 2 main energy systems which depend on the fast release of carbohydrates and an anaerobic form of metabolism called Glycolysis. During this period, lactic acid is produced.
After 2 minutes and onwards, a 3rd energy system is employed which allows the muscle mitochondria to break down the stored sugar in the form of glycogen and Free Fatty Acids (FFA) via a process called oxidative phosphorylation to release the ATP (energy) that your muscles need for contraction.
It is best to have a combination of both Cardiovascular and Resistance/Weight training. Resistance does not mean needing very heavy weights.
This can be in the form of resistance bands, using a 500ml bottle of water in each hand, a 10 lb medicine ball or even using your body weight.
HIIT is a good starting point as it provides a good metabolic work out without using too much time – it has a high Calorie burn to time ratio.
HIIT has been found to provide physiological health benefits 1:
As well as 2
There are two main types of skeletal muscle in our bodies - the Type 1 (slow twitch) which is responsible for the low intensity and long duration type of exercise (i.e. long distance running) and the Type 2 (fast twitch) which is the intense short term heavy work out exercise. Our muscles have different combinations of the two.
The premise is to keep pushing your metabolism through a duration of between 10 to 20 mins and this needs to be intense (i.e. you can just about talk but cannot sing).
This may be performed in a living room or small office space - you just need a yoga mat and a floor area of 180cm x 100cm
Aim to reach a target heart rate according to this rough formula:
220 – Age = Maximum Heart Rate.
For someone who is starting out, it is better to aim for 60 to 75% for the first two weeks of training.
But to achieve real health benefits which you would derive from HIIT – the heart rate you reach should be between 85 to 95% of the maximum. For someone aged 45,
i.e. 220 – 45 = 175 bpm
then 85 – 95% of 175 = 149 to 166bpm
I have arranged this so you are trying to alternate between working on the upper and lower parts of your body so you get a full body work out. If you find one cycle too easy, you can repeat the cycle another two times. One cycle should last around 8 mins.
If you have not been exercising much, you should start off doing this three times per week on non consecutive days for the first 2 weeks. Once you get fitter, ideally you want to aim for 5 times per week.
Please note that this is a basic regime – to get greater health benefits, requires a more vigorous work out which will be discussed in a future article.
If you have:
Please consult a doctor first before you start doing this type of intense exercise.
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