How much do you sleep at night?
wim: Funny to see this post here today, as last day was actually one of those work-round-the-clock days (1h powernap), I usually try to aim for at least 6 hours. Less than that just makes me less efficient at work and I start skipping sports for the day ;). I usually have one day per week where I sleep really a lot, like 10 hours or so, which feels like it sort of recharges me for the week.