March 15, 2016 10:42 PM

March Madness With a Dose of Sleep Science

For one sleep scientist, the circadian rhythm could be key to a great March Madness bracket.

When it comes to March Madness, Cathy Goldstein, M.D., M.S., might have an edge over her fellow bracketologists.

The neurologist at the U-M Sleep Disorders Center is combining her basketball fandom and sleep science expertise as she makes her round-by-round selections this season. Below, she explains how circadian rhythm plays into her picks.

What are circadian rhythms?

Goldstein: Circadian rhythms are the body’s 24-hour biological processes that help us react in an appropriate manner to the daily light-dark cycle. The most apparent circadian rhythm is the sleep-wake cycle. Your internal clock promotes being asleep at night and being awake during the day. Light is the biggest factor that modifies our circadian rhythm — lots of light in the evening can make us more of a night owl, while bright light in the morning can make us more of a morning lark.

How does the circadian rhythm relate to college basketball?

Goldstein: Along with sleep, there are also circadian rhythms for performance, and we don’t perform as well when our body thinks it’s time to be asleep.

About two hours before your normal bedtime, your melatonin starts to rise. For example, if you are typically asleep by 11 p.m., your melatonin will start to rise at about 9 p.m. You’ll get sleepy, your body temperature will drop, and physical performance declines.

Research shows that the peak time for athletic performance is late afternoon and early evening. That means the college basketball teams playing at a biological late afternoon or early evening time have a circadian advantage, a term coined by sleep specialist W. Christopher Winter.

"College basketball teams playing at a biological late afternoon/early evening time have a circadian advantage."
Cathy Goldstein, M.D., M.S.

How do you make a March Madness prediction based on circadian rhythm?

Goldstein: A lot of travel is involved for the March Madness games, so I investigated where each team is from, where the game is located, and what time the game starts. Just because the clock on the wall changes doesn’t mean your internal clock does. So the players’ internal clocks will be set to their home time.

For example, let’s look at the USC and Providence game. The game is in the Eastern time zone (Raleigh, North Carolina), so the Providence players’ body clocks will think it’s indeed 9:50 at night. But the USC players visiting from Pacific time will feel like it’s 6:50 p.m., closer to peak performance time. The Providence players’ bodies will be starting to prepare for sleep by game time. Both teams have similar rankings, so I used circadian predictions to make my pick: USC. Circadian advantages have been shown in both Major League Baseball and Monday Night Football games, when the West Coast visiting teams performed significantly better than East Coast home teams, beating the point spread twice as often in the study of NFL games!

I used the same process to pick Gonzaga over Seton Hall (7:57 p.m. MDT Thursday). The game will be played in Denver, but it will be close to bedtime for Seton Hall — while being close to peak time for Gonzaga. This one was a little riskier, because Seton Hall is rated higher. I’m hoping Gonzaga uses their circadian advantage to get a win.

Alternatively, California (ranked fourth) plays Hawaii (ranked 13th) on Friday. They play in the Pacific time zone (11 a.m. PDT), which is the time zone the California players are used to. The Hawaii team members’ body clocks are two hours behind, playing at 9 a.m. Because college students tend to be night owls, this early wake-up for the Hawaii team puts them at a circadian disadvantage, so I made my pick: California.

But circadian advantage isn’t the only predictor. When I looked at the Xavier (ranked second) and Weber State (ranked 15th) game (8:15 p.m. CDT Friday), I saw that Weber St. has a circadian advantage. However, it’s not a big enough time difference for me to pick the lower-ranked team, so I stuck with Xavier on this one. I think they’ll be able to overcome their circadian disadvantage.

Is it like jet lag?

Goldstein: No, this is a different scenario than jet lag because the trips are so short that the players’ bodies won’t align to the new time zone before the game. Their bodies will stay on the time of origin, which could be an advantage or a disadvantage depending on game time and location.

Alternatively, the NFL games in London have a much larger time difference to overcome, so there are big discrepancies between local time and internal time. Because of those changes, some teams like the New York Jets even brought in sleep consultants so players could learn how to overcome jet lag.

What should the team with the circadian disadvantage do to overcome it?

Goldstein: If your team is playing at a time that would normally be very late in the evening, you are at a circadian disadvantage. I suggest those players try to align their internal clocks to the game time by pushing their body clock later. That means sleeping in, practicing at night, and using bright light in the evening to suppress melatonin and delay the circadian rhythm.

Alternatively, if you’re playing an early game, I suggest you practice at that time and get bright light in the morning to push your body clock earlier to enhance performance earlier than your body is used to.

Should I change my whole bracket now?

Goldstein: Don’t get out the eraser just yet! Sometimes one team is inherently better than another and the circadian rhythm may not make enough of a difference. It certainly doesn’t apply to all the games, but for the matchups that cross time zones, especially when the teams have similar standings, circadian science is my key.

Sweet 16 update 3-22:

With the Sweet 16 set, how did circadian advantages play out in early rounds?

Gonzaga beat Seton Hall as predicted in round one and also won its round two game over Utah. On the flipside, Providence overcame its round one disadvantage and beat USC — before falling to North Carolina in round two. Likewise, as predicted, Xavier’s skill advantage was big enough to overcome the circadian disadvantage the team faced in round one against Weber State. Xavier did fall in round two to Wisconsin in a close game.

Hawaii ended up having no circadian disadvantage after all. Why? Because the team spent three weeks on the mainland in advance to get aligned with local time.

Advantages are less straightforward as the tournament continues, since all the teams have been on the road. Nonetheless, a couple of circadian advantages come to mind for the Sweet 16.

Dr. Goldstein is picking Gonzaga over Syracuse (8:40 p.m. CDT Friday). In theory, Gonzaga’s body clocks will still be set closer to peak performance time of 6:40 p.m., while Syracuse will feel like it’s 9:40 p.m.

She’s also taking Oregon over Duke (6:55 p.m. PDT). Oregon players should feel on track in their own time zone, while Duke may be getting a bit sleepy.

Final Four update 3-29:

The Final Four is set — and the circadian advantages are now gone. (Three teams come from the Eastern Time Zone, and one is from the Central Time Zone). How did Dr. Goldstein’s picks do?

Like any brackets, Dr. Goldstein picked plenty of winners and some losers.

For instance, in the Sweet Sixteen, Oregon indeed used its circadian advantage to topple Duke. But Syracuse was anything but sleepy in wiping out Gonzaga’s circadian advantage, eventually making it to the Final Four. Oregon didn’t fare as well, losing to Oklahoma in the Elite Eight.

“In the end, performance is complicated, and there are many other factors that will have greater impact on success on the court than circadian rhythms,” Dr. Goldstein notes. 

The age of the players may be a factor, given how many college students are night owls. A recent study showed a strong correlation between the number of late chronotypes (night owls) and the time of a team’s peak performance, with peak performance being later in the. Frequent travel and changing game times may have shifted players’ internal clocks, too, and reduced the circadian advantage over time.

Sleep duration is critical, too. In a study of Stanford basketball players, when sleep duration was extended an average of 100 minutes for five to seven weeks, researchers saw increases in speed, shooting accuracy, free throw and three-point percentages. 

“It comes down to this: Well-rested players may have performed better regardless of circadian timing,” Dr. Goldstein says.