More wild speculation here, but here goes....
Sealife in the antartic ocean is generally much larger than thier equivalent species found elsewhere in the world. They are real life monsters by all accounts. It's been suggested that the reasoning behind this is the intense cold water. Note these organisms also have tiny metabolism's.
Apparently, water at freezing temperatures permits a far higher density of O2 within it, and its this extreme availability of oxygen that allows these organisms to grow so large.
Theres studies floating around on pubmed showing how Nitric Oxide ( from arginine ingestion or beet root juice ) enhances exercise, most likely through the vasodilation and therefore allowing a higher density of oxygen to come through.
It may therefore be beneficial to ingest beet root juice / arginine along with Niacin for the flush (which also causes vasodilation) post-workout to maximise the uptake of oxygen and post-workout feeding nutrients.
I'm not sure how long Nitric Oxide remains elevated after arginine / beet root juice, but the niacin flush lasts only 30mins-2 hours. This is when it could be best to consume those post-workout nutrients.
UPDATE :- upon further thinking, this could also be where the beneficial effects of stretching come into play, by increasing blood flow through the muscle. Stretching just before bed might be effective in promoting more nutrient influx to your exercised muscles.
UPDATE II :- I stumbled on some research suggesting stretching actually induces hypoxia in muscle. Therefore I dont recommend it before bed or after exercise, but it may help before exercise.