Manage your energy, not your time

3:30 p.m. You read the same email for the third time and it still won't go in. You grab a third coffee, sit back down, open one tab and then another. In the evening you need a glass of wine to switch off. On Saturday you check your inbox "just to see if anything urgent came in." And on Monday you start the week already tired. You haven't done anything heroic, and yet you're always exhausted. Maybe the problem isn't how much time you have. Maybe it's that you need to manage your energy, not your time.

Hours are fixed, energy isn't

Jim Loehr is a sports psychologist who spent decades working with tennis champions like Monica Seles, Pete Sampras and Arantxa Sánchez Vicario. With the journalist Tony Schwartz he wrote The Power of Full Engagement, a book that starts from a simple line: the number of hours in a day is fixed, but the quantity and quality of energy available to you is not.

That's why, the authors argue, the resource you really need to manage isn't time. It's energy. You can spend ten hours at the office, but if you arrive running on empty, those hours aren't worth much.

Loehr and Schwartz make a comparison that's hard to shake. A professional athlete spends about 90 percent of their time training in order to perform the other 10 percent. They get an off-season of four to five months a year. We, on the other hand, are expected to perform at our best for eight, ten, twelve hours a day, with a few weeks of vacation, often spent checking email. And we've never trained for it.

Why you're always tired: what happens between points

The book's central idea was born on a tennis court. Loehr spent hundreds of hours studying matches between the world's best players to figure out what set them apart. During the points themselves, he could find almost no difference. Then he looked at what they did between points.

The best players, mostly without realizing it, all had the same routine: the way they walked back to the baseline, how they held their head and shoulders, where they focused their eyes, the rhythm of their breathing, even what they said to themselves. When Loehr measured their heart rates, he found that in those sixteen to twenty seconds they could drop by as much as twenty beats per minute. Lower-ranked players had no recovery routine at all. Their heart rates stayed high for the whole match, and by the third set they were more tired, more frustrated and less sharp.

Now think about your own day. Meeting, email, call, deadline, more email. No time between points. The authors call it living "linearly": spending energy nonstop without ever renewing it. And they point out that if you need several cups of coffee to stay alert during the day and a couple of drinks to unwind at night, you're simply masking that linearity.

Manage your energy: live in sprints, not a marathon

Your body runs in cycles. At night, sleep moves through phases of roughly 90 to 120 minutes. In the 1970s, researchers found that something similar happens while we're awake: for an hour or so we're more alert and focused, then our energy dips. Somewhere between 90 and 120 minutes, the body starts asking for a break. You know the signs: yawning, hunger, tension, trouble concentrating, the urge to procrastinate, more mistakes.

We can override those signals, but only by leaning on stress. It works for a while. Then the bill arrives as irritability, impatience, headaches, restless nights.

Loehr and Schwartz offer an image: picture a long-distance runner and a sprinter. The first often looks worn down. The second is bursting with energy, because the finish line is a hundred meters away. We should live more like sprinters: periods of full engagement, followed by real recovery. It's the same logic as deep work blocks: ninety minutes of full focus, then genuinely switch off.

Rituals, not willpower

So how do you change? Not with willpower, the authors say, which is a far more limited resource than we think. If you have to decide to take a break every single time, sooner or later you'll stop taking them.

What you need are rituals: precise, repeated behaviors that become automatic over time. Like brushing your teeth. You don't have to remind yourself, it just happens. A ritual doesn't push you. It pulls you.

There's another idea that flips the way we think about fatigue. Stress isn't the enemy. A muscle grows precisely because it's put under strain, but it grows during recovery, not during the workout. The same goes for focus, patience and creativity. The problem isn't working hard. It's never recovering.

Your sprints for tomorrow

You don't need to overhaul your life. You just need to build in the time between points.

1. Work in 90-minute blocks. One in the morning, one in the early afternoon, on your most demanding work.
2. Between blocks, actually recover. Ten minutes away from the screen: a walk, a few deep breaths, a chat that isn't about work. Scrolling your phone doesn't count.
3. Listen to the signals. When you've read the same line three times, don't reach for another coffee. Get up.
4. Create a ritual to close the workday. Write down tomorrow's three priorities, close the laptop, change rooms. From that point on, you're in recovery.

Tomorrow at 3:30, the fatigue will still show up. But this time you'll know it isn't a flaw. It's the signal that it's time for the space between points.