Mengantuk selepas makan???

Do you feel sleepy after eating a large/heavy meal? Chances are, you will and I am writing this post to inform you that it is normal to feel so...

I stumbled into this while reading on somnolence... They even have a medical term for this situation, which is Post-prandial somnolence...

Post-prandial somnolence is a state of drowsiness or lassitude following a meal. 

Post-prandial somnolence has 2 components:

- a general state of low energy related to activation of the parasympathetic nervous system in response to nutrients in the gastrointestinal tract, 

- a specific state of sleepiness caused by hormonal and neurochemical changes related to the rate at which glucose enters the bloodstream and its downstream effects on amino acid transport in the central nervous system.

Parasympathetic activation

In response to the arrival of food in the stomach and small intestine, the activity of the parasympathetic nervous system increases and the activity of the sympathetic nervous system decreases.

This shift in the balance of autonomic tone towards the parasympathetic system results in a subjective state of low energy and a desire to be at rest, the opposite of the fight-or-flight state induced by high sympathetic tone. 

The larger the meal, the greater the shift in autonomic tone towards the parasympathetic system, regardless of the composition of the meal.
  

Insulin, large neutral amino acids, and tryptophan  

When foods with a high glycemic index are consumed, glucose is absorbed rapidly from the gastrointestinal tract into the bloodstream, and in individuals with normal carbohydrate metabolism, insulin levels rise concordantly to drive glucose in to the body's tissues and maintain blood glucose levels in the normal range. 

Insulin stimulates the uptake of valine, leucine, isoleucine, and tyrosine into skeletal muscle, but not uptake of tryptophan. 

This lowers the ratio of these large neutral amino acids in the bloodstream relative to tryptophan, making tryptophan preferentially available to the large neutral amino acid transport at the blood-brain barrier. 

Uptake of tryptophan by the brain thus increases. In the brain, tryptophan is converted to serotonin, which is then converted to melatonin. 

Increased brain serotonin and melatonin levels result in sleepiness that has been objectively measured.

Conclusion: 

Feeling sleepy after eating is normal, it does not mean you are an extremely lazy person... However, certain strategies can be used to prevent this sleepiness...

First, don't eat too much (large meal)... Eat small and frequent meals...

Second, avoid high glycemic index food (such as white rice)... 

Third, don't do sleep-inducing activities (such as studying) directly after meal... Do something enjoyable and stimulating such as facebooking, chatting with your friends (online or offline), or solat sunat... Anything to keep you awake until it is not that sleepy anymore (maybe until 30 mins after meal)...

If you have time constrain and do not wish to fall asleep on a certain day, try these strategies... InsyaAllah boleh kut tahan mengantuk tu... hehe