Pretty much everything that happens in our bodies is governed by the complex interaction between light and our biology known as our circadian rhythm. In this short video, the boys over at AsapSCIENCE take us through a full 24-hour cycle, and it really drives home just how much is going on behind the scenes while we're working on getting through our days. It also reveals when the best time to shave, exercise, and do your most challenging work is, according to your biology.

When you wake up, you might feel groggy as a result of sleep inertia. But pretty soon your blood pressure will start to increase and there'll be a 50 percent rise in the stress hormone cortisol to help you get ready for your busy day. This is also the best time to shave, because clot-forming platelets are most abundant, which means less bleeding from cuts.

Next, it's time for caffeine and the office. Depending on your age, your mental activity peaks around 2.5 to 4 hours after you wake up - so, for most of us, late morning - and declines as the day progresses until the evening, when our biological clock turns off the proteins involved in forming long-term memories. But if you're a young adult, research suggests that pattern may actually be reversed, as the team over at AsapSCIENCE explains.

But regardless of age, if you're planning to work out, you're better off hitting the gym at around 4.30pm, rather than in the morning, with research showing that people build around 20 percent more muscle strength in the afternoon.

As the night drags on, your pineal gland starts to release melatonin, preparing you for sleep. But that doesn't mean your body is about to get some rest. In fact, your brain is as busy during REM as it is during the day.

So what's it doing at night? And when is the best time to eat, make love, and get drunk? Watch the episode above to find out. Trust us, it'll make you appreciate your body so much more.