There was a really interesting Op-Ed in Sunday’s New York Times by Tony Schwartz at The Energy Project. As any good Scrum Master knows, finding a sustainable pace for the team is incredibly important to increasing velocity.
At Scrum Inc., we talk about avoiding Muri aka STRESS because when people are stressed they do poor work. (Last year, Jeff wrote a blog post about how eliminating overtime at his Venture Capital group increased Velocity by 160%.) We recommend that Team members don’t work more than eight-hour days and that Scrum Masters avoid death marches. This isn’t just out of kindness and respect for Team; it’s because people get more work done if they aren’t stressed out.
Swartz sites a number of studies:
Spending more hours at work often leads to less time for sleep and insufficient sleep takes a substantial toll on performance. In a study of nearly 400 employees, published last year, researchers found that sleeping too little — defined as less than six hours each night — was one of the best predictors of on-the-job burn-out. A recent Harvard study estimated that sleep deprivation costs American companies $63.2 billion a year in lost productivity . . .
In the 1950s, the researchers William Dement and Nathaniel Kleitman discovered that we sleep in cycles of roughly 90 minutes, moving from light to deep sleep and back out again. They named this pattern the Basic-Rest Activity Cycle or BRAC. A decade later, Professor Kleitman discovered that this cycle recapitulates itself during our waking lives.
The difference is that during the day we move from a state of alertness progressively into physiological fatigue approximately every 90 minutes. Our bodies regularly tell us to take a break, but we often override these signals and instead stoke ourselves up with caffeine, sugar and our own emergency reserves — the stress hormones adrenaline, noradrenaline and cortisol.
Working in 90-minute intervals turns out to be a prescription for maximizing productivity. Professor K. Anders Ericsson and his colleagues at Florida State University have studied elite performers, including musicians, athletes, actors and chess players. In each of these fields, Dr. Ericsson found that the best performers typically practice in uninterrupted sessions that last no more than 90 minutes. They begin in the morning, take a break between sessions, and rarely work for more than four and a half hours in any given day.
Taichi Ohno, the father of the Toyota Production System, referred to stress from overwork as unreasonableness. Check out Ohno’s other stress impediments at ScrumLab and read Schwarz’s entire Op-Ed here.
- Joel Riddle