Why is it wrong to say that humans evolved an instinct to exercise?
According to the book, humans did not evolve an instinct to exercise. In fact, humans evolved in a way that conserves energy, because our ancestors faced more problems with food shortages. Human nature is more inclined to rest rather than exercise. This can be seen from the low human PAL value, which shows that we tend to conserve energy.
Did humans evolve to rest or run?
According to the analysis in the book, humans evolved more to rest than to run. Evidence includes:
- Humans have a low PAL(Physical Activity Level) value, indicating a tendency to conserve energy
- Studies show that humans spend most of the day in light physical labor, with a maximum of 1 hour of strenuous physical labor
- Humans can reach activity levels comparable to hunter-gatherers by walking 1-2 hours per day
In summary, humans evolved more to rest than to run or engage in other high-intensity physical activities.
How are sitting and smoking different? Is prolonged sitting really unhealthy?
Prolonged sitting and smoking are different, although both increase inflammation and disease risk, smoking is more harmful. Prolonged sitting is indeed unhealthy for the following reasons:
- Prolonged sitting causes adipose dysfunction, leading to chronic mild inflammation
- Prolonged sitting reduces the body’s ability to absorb nutrients from the blood
- Prolonged sitting increases stress hormone levels, which also triggers inflammatory responses
However, the harm of prolonged sitting is much less than smoking. The key to improving prolonged sitting is appropriate physical activity, not posture.
Why does stress affect rest? Do we really need 8 hours of sleep every night?
Stress increases cortisol and other stress hormone levels, leading to sleep deprivation. However, there is still controversy over whether humans really need 8 hours of sleep every night.
- Studies show that 7-7.5 hours of sleep have lower mortality rates than 8 hours of sleep
- Hunter-gatherers sleep less than 8 hours
- The elderly usually sleep less
In summary, stress does affect sleep quality, but the requirement of 8 hours of sleep every night may be too high. Sleep quality is more important than quantity.
Why is it wrong to say that running damages the knees?
This is a misconception. Appropriate amounts of running can actually enhance knee health for the following reasons:
- Running can improve cartilage health and protect joints
- True risk factors increasing knee problems are obesity and lack of exercise
- Running mileage needs to be increased progressively to allow joints to adapt
In summary, appropriate running does not damage knees, but has benefits. The key is to increase mileage progressively, not suddenly.
Is unwillingness to move normal as you get older?
This view is also wrong. Studies show that compared to people who exercise regularly, people who do not exercise are more likely to “age prematurely” for the following reasons:
- Long-term exercise can delay the onset of various diseases
- If healthy, the physical abilities of elderly hunter-gatherers are close to middle-aged people
- Lack of exercise accelerates the aging process
Therefore, unwillingness to move should not be seen as a normal part of aging. Maintaining appropriate exercise can slow down the aging process.
Can you just start exercising if you want to start exercising?
It may not be appropriate to boldly start high-intensity exercise. You should progress gradually for the following reasons:
- Suddenly starting high-intensity exercise, dopamine receptors cannot adapt and you cannot obtain the pleasure of exercise
- It takes time to train before you can get the endorphins rewards from exercise
- You should choose exercise projects you are interested in
- Reasonable short-term goals should be set and reward yourself
In summary, starting exercise should not be rushed, exercise volume should be increased gradually, while considering personal interests and reward mechanisms.