I’m toiling away on my laptop, getting lots of work done. Notes are being reviewed, interviews are being prepared, and I’m exchanging instant messages with two colleagues. This productivity is great! But I feel so, so tired. Like I should be under the covers instead of checking off my endless to-do list. That’s because it’s bedtime, 11 p.m., and I’m home in my striped pajamas. This isn’t an anomaly or the result of a new deadline or an unusually busy week. It’s my normal nighttime routine—and probably yours, too.