In the Rhythm of Each Breath We Take Quiz

Our sleep is deepest between the hours of 4 and 6 AM.

Most things we do follow circadian (from Latin - circa: about, diem: day) rhythms, which make sure our bodies don't try to do everything at once. We have a clear sleeping and waking cycle. Melatonin is a hormone that our bodies produce when it gets dark, to help us sleep, reaching a peak between 4 AM and 6 AM. These are also the hours where concentration is most difficult, our body temperatures are lowest, and death is most likely.

Our pain intensity, including toothache, and the sensitivity of our skins tends to be highest in the evening between 8PM and 10PM. Toothache is at its least painful just after lunch, between 2PM and 4PM.

Our circadian rhythms are adjusted and fine tuned by our exposure to natural light. When volunteers have been deprived of natural light for periods of time, their body clocks have shifted so drastically that after a fortnight they were found to be going to bed at midday.

Labour pains are most likely to start between midnight and 2 in the morning, and most natural births occur in the early hours of the day. Between midnight and 2AM is also a prime time for becoming sleepy, and ovulation.

When our internal clocks are disrupted, we can suffer jet lag or more serious symptoms, like sleep disorders or even depression. We are most vulnerable to making mistakes when up in the early hours - the Chernobyl disaster happened at 1.23 AM, and the Exxon Valdez oil spill just after midnight.

Allergic reactions are likely to be highest between the hours of 10PM and midnight. Also peaking in this time slot are menopausal hot flushes, while stomach activity peaks between 8PM and midnight. Libido has two peaks in the day, one of which is 10PM to midnight, with the other between 6AM and 8AM.

Muscle strength is, on average, greatest between 4PM and 8PM. Also peaking during this time slot are heart efficiency, lung function, flexibility, and the strength of our grip and handshake.

The pain intensity we experience is lowest between the hours of 8 AM and 10 AM. Bowel movement peaks in this time slot. The hours between 6 AM and 10 AM are most risky for cardiac death and strokes.

Kidney function and urine production reduces while we sleep and reaches its lowest between 2 and 4 in the morning. It's obviously helpful to reduce our need to urinate to help our sleep. The same time slot is where asthma suffering tends to reach a peak.

Endorphin levels reach a peak between 2 PM and 4 PM. Endorphins are chemicals released by the pituitary gland that reduce our body's experience of pain, and increase our sense of well-being. Levels of serotonin, a chemical affecting our mood, cognition, and many other things, peak in the same time slot.

Our best chance of conception is between the hours of 6 AM and 8 AM. This coincides with one of the two peaks in libido. Sadly, migraine and hay fever also peak at the same time. The level of cortisol, a chemical that increases blood sugar, and aids metabolism, among many other things, also peaks now.

Our concentration levels tend to peak between the hours of 10AM and 2PM. This is the best time for logical reasoning and complex puzzle solving. The time to avoid for this activity is between 4AM and 6AM.