I did not want to stop swimming, and wanted to check whether I could double my usual these days distance. I did not care much about the style and speed, I just wanted to move forward in water, because nothing better waited for me outside on this emotionally excruciating day.
264 length (25 yards), 6 km total, in almost 3:07 (187 minutes). Six kilometers should constitute 4 swimmer's miles. First 200 I made in 2:20, first 5 km - in 2:35 (155 minutes).
Compared to the similar distance swims in the ocean, where the main problem was dropping of the body temperature by the third hour despite keeping the same speed (more or less), swimming in pool for so long irritated my skin. I inhaled too much chlorine! There also was a need to change lanes to give the space for team training, and the constant turning became annoying.
The great thing was to see the pool with lights after darkness, it was fun to swim towards a black cross on the wall with two lamps on the sides.
Vitamin B3, Niacin, nicotinic acid, helps to convert food into energy and is essential for healthy skin, blood cells, brain, and nervous system. It is one of 8 B vitamins. It is water-soluble, which means it is not stored in the body. It has 2 other forms, niacinamide (nicotinamide) and inositol hexanicotinate, which have different effects.
Niacin occurs naturally in food and can also be made by your body from the amino acid tryptophan, with the help of B6.
It is rare for anyone in the developed world to have a Vitamin B3 deficiency; alcoholism is the main cause of it in the US.
Recommended daily amount: 14 - 16 mg.
Example sources: whole grains, mushrooms, peanuts and other legumes.