The 4 Pillars of Health

What kind of exercise should I do and for how long?

All kinds of exercise are beneficial for our bodies. There is no one exercise which is better than another. It is more important that you enjoy the exercise you are doing so that it is sustainable. However, if you have a short-term specific goal, such as gaining muscle mass, you might be able to sustain strength training for a specific period even though you might not enjoy the exercise.

Sometimes I have to drag myself to go for a run even though I don’t feel like it. But most of the time I felt good after doing it and subsequently I remind myself of the reward that awaits me if I can endure the initial resistance.

WHO recommends that adults aged 18 to 64 should do the following

  1. 150 mins of moderate-intensity aerobic activity per week or 75 mins vigorous-intensity aerobic activity
  2. For added benefits, should increase to 300 mins or 150 mins respectively
  3. Muscle strengthening activities on 2 or more days per week

For more details on the recommendations, please refer to

Some of the benefits of exercise include

  1. lower rates of chronic illnesses such as CVD, Type 2 Diabetes, high blood pressure, metabolic syndrome etc
  2. less likely to have hip or vertebral fracture
  3. better cardio and muscle fitness
  4. easier to maintain normal BMI and body composition
  5. improve energy levels and better sleep
  6. faster recovery from minor illnesses

Any form or type of exercise is good for you. But I would recommend doing something you enjoy so that you can keep doing it. You may engage in either group or solo exercises. Solo exercises are good when you can’t gather your friends. I used to play volleyball but now I do running as it is easier to just put on a pair of shoes and go.

Many over-weight people start jogging first to lose weight and end up with knee or joint pains. If you are overweight, focus on changing your diet first before exercising. Cut out as much processed food and carbs as you possibly can. Your weight will start to go down after 1 week. After 4 weeks, your body will slowly become fat-adapted. Your energy levels will rise and you will be in better shape to start exercising. This approach is also better for your knees as by then you will have less weight to support. This is also because exercise is only 10% effective in losing weight compared to diet which is 90% effective.

Effects of Duration and Intensity of Physical Activities on Mortality

There is no question that exercise reduces the risk of heart disease and improves our overall health. (Ref A) The only question is whether too much exercise will put a person in any health risk.


Reduced risk of dying

No exercise


Base 150 mins of moderate exrecise


2 x base


3 to 5 x base


5 x base and above


The information above is taken from Harvard Medical School Health Publishing website. 

As you can see, the risk of dying is reduced when the exercise duration is increased, but only up to 5 times the base of 150 minutes. Thereafter, there is no additional benefit if you exercise longer.

How about the intensity of the exercise? Will vigorous-intensity activities provide more benefits than moderate-intensity activities?

According to a study published in 2018 (Ref B), as long as the minimum guideline of 150 mins of exercise is met, there is no difference in mortality rates between moderate or vigorous intensity activities.

However, another study (Ref C) reported that vigorous intensity activities provided greater reductions in mortality risks while the duration of vigorous exercise did not provide any difference in risk. Another study also has the same conclusion. (Ref D)

My recommendation is to start slow and gradually increase your duration OR intensity. Try not to increase BOTH at the same time to prevent unwanted injuries. Set realistic goals instead of ambitious ones such as running a marathon in 16 weeks if you have not been running an average of 30km per week previously.

You may refer to WHO’s definition of moderate vs vigorous intensity activities.

Ref A     Myers, J. (2003). Exercise and cardiovascular healthCirculation107(1), e2-e5.

Ref B     Kikuchi, H., Inoue, S., Lee, I. M., Odagiri, Y., Sawada, N., Inoue, M., & Tsugane, S. (2018). Impact of Moderate-Intensity and Vigorous-Intensity Physical Activity on MortalityMedicine and science in sports and exercise50(4), 715-721.

Ref C     Lopez, J. P. R., Gebel, K., Chia, D., & Stamatakis, E. (2019). Associations of vigorous physical activity with all-cause, cardiovascular and cancer mortality among 64 913 adultsBMJ open sport & exercise medicine5(1).

Ref D     Gebel, K., Ding, D., Chey, T., Stamatakis, E., Brown, W. J., & Bauman, A. E. (2015). Effect of moderate to vigorous physical activity on all-cause mortality in middle-aged and older Australians. JAMA internal medicine, 175(6), 970-977. 

Should Athletes worry about a high-carb diet?

I know there are many coaches and athletes that say carbs are essential for speed. It is true that glucose can provide faster energy as our body burns glucose faster than fats. However, if you are running for more than 60 mins, it is better for you to train your body to be fat-adapted and burn fats for energy instead. Once you are running on fats, you won’t even need to ingest sports gels in order to perform well. (Ref E)

Do athletes develop Type 2 Diabetes (T2D)? Certainly. Prof Tim Noakes is a marathoner and he ended up being diagnosed with type 2 diabetes. That made him rip off a whole chapter on ‘Carbohydrate Loading’ from his book, ‘The Lore of Running’.

Watch from 6:55 to 8:25 Prof. Tim Noakes – ‘Medical aspects of the low carbohydrate lifestyle’

So unless you can burn off all the carbohydrates that you consume on a daily basis, any access carbs will be turned into fats after your glycogen stores are full. You will slowly become insulin resistant due to the constant high levels of insulin in your blood and eventually develop T2D. As such, it doesn’t mean that as long as you are physically active, you will not develop T2D. It depends on your carbohydrate tolerance and your insulin sensitivity. You will become insulin resistant if you have low carbohydrate tolerance and you eat a lot of carbs (>50% daily caloric intake). If you have low insulin sensitivity, you will develop chronic illnesses.

If you intend to engage in vigorous exercise for as old as you live, it is better for you to become fat-adapted as soon as you can. I will share my experience soon in a later post.

Ref E      Malhotra, A., Noakes, T., & Phinney, S. (2015). It is time to bust the myth of physical inactivity and obesity: you cannot outrun a bad diet.

You can’t Exercise away a Bad Diet

If you have been exercising diligently for more than 5 hours weekly but your weight did not barge, chances are you are not eating right. Many people misunderstand the ‘Calorie In Calorie Out’ (CICO) concept. CICO means that your weight will reduce if your total calorie intake is less than the calories that you burn off and vice versa. The complicated part about CICO is that calories from different foods give out different amount of energy in our body. Even if you can calculate accurately the amount of calories that you are consuming, it is very difficult to calculate how much energy your food intake produces, how much energy is needed by your body to process the food, how your body uses the energy and stores the excess energy if any.

If your diet consists of mainly carbs or processed food or vegetable oils, you won’t lose much weight no matter how much you exercise. Conversely, if your diet consists of real foods, you don’t even need to exercise much and you can maintain a healthy weight. 1000 calories of carbohydrate is not the same as 1000 calories of protein after your body digest them because it takes more energy to digest proteins than carbohydrates, giving you a lower nett amount of energy from proteins. Moreover, protein makes you satiated and keeps your hunger hormone Ghrelin low for a long time (> 3 hrs) whereas Ghrelin might be lowered more initially after eating carbs, but it will rebound after 2 hrs, making you hungry again. As such, you might end up eating more calories thinking you have burned off the calories already.

In conclusion, what you eat is more important than how much you exercise.