Dear Doctor,

I always doze off during the daytime, especially after lunch. It has now become a habit and I don’t know if its a health problem or it is just that I’m tired. The interesting thing is that I always go to bed early and I sleep well the whole night. Please advise me on what I should do to avoid this. Mugisha

Dear Mugisha,

Feeling sleepy after lunch is a fairly common thing. Now whether one sleeps after lunch or overcomes the somnolence, depends on many factors. Amount and quality of food taken, whether breakfast has been taken or skipped, whether one has had adequate sleep in the night or not, are factors which can determine the extent of sleepiness.

After a meal, blood glucose levels rise, leading to increase in blood insulin levels to neutralise it. Insulin leads to increase in blood serotonin and melatonin levels. Both of these neurochemical transmitters have a calming effect on the brain and give a "feel good” feeling, thus inducing sleep. High carbohydrate food leads to increased levels of these chemicals. Foods with high protein content like spinach, tofu, eggs, or cheese, contain high levels of tryptophan, which augments level of melatonin. White bread is a food where the breakdown products are absorbed quickly after being consumed, in contrast to multi-grain bread. This causes spike in blood sugar levels which fall quickly as well, leading to lethargy and somnolence.

After a meal, more blood is diverted to the gut to facilitate digestion, thus affecting the blood supply to the brain and slightly producing lethargy and somnolence. The body takes longer to digest a fatty meal or heavy meal, thus causing somnolence. When a person skips breakfast, they are more likely to eat a heavy meal and feel sleepy. A person who has not slept well in the night before is also likely to sleep more after lunch.

To prevent day time somnolence, it is advisable to take small frequent meals, including breakfast. Food should be balanced including more whole grains, nuts, fresh fruits and vegetables. Drinking an adequate amount of water makes one feel fresh and removes lethargy. Regular physical exercise regulates the blood circulation and oxygen consumption of the body, thus removing lethargy and somnolence. Timely and sufficient sleep in the night ensures that the body is rested completely and daytime somnolence does not occur after a meal. On feeling sleepy after lunch, an individual can move out and take a short walk or do some deep breathing.

If in spite of the above measures excess somnolence occurs after lunch, a person should go for a medical check up to exclude a nutritional deficiency or some other cause of weakness.

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