A study published in April 2026 by researchers at the University of Toronto found something that most leaders already sense but rarely act on: on days when people feel mentally sharp, they set higher goals and complete significantly more work, roughly 40 extra minutes of productive output compared to their low-energy days.
Forty minutes. Every day. Depending on which version of yourself shows up.
The myth of the consistent performer
We build teams around the assumption of consistency. Targets are set, deadlines are fixed, and the expectation, usually unspoken, is that people will show up at roughly the same level every day. When they don’t, we call it a performance issue. We schedule more meetings. We add more oversight.
Organisations that keep pushing for consistent output without accounting for natural fluctuation in human energy will always find themselves frustrated by the gap between what their teams are capable of and what they actually deliver. The design of how work gets done matters as much as the expectations placed on it.
Sleep, stress, hydration, personal circumstances, accumulated pressure, all of it moves the needle on performance, day by day, sometimes hour by hour. People are not machines, and their output reflects that reality whether we acknowledge it or not. The leader who understands this shifts their focus from managing outcomes alone to managing the conditions that make good outcomes possible.
What happens when we ignore it
Here is the part that should concern every leader: employees who push through low-energy days without adjustment are not just less productive. They are more likely to make significant errors, the kind that cost time, money, relationships, and trust.
A sluggish mind forced through high-stakes cognitive work- a strategic decision, a sensitive client conversation, a complex analysis – is operating at a deficit it cannot always detect. The person sitting at the desk often doesn’t know they’re impaired. They think they’re just a bit tired, and their judgement doesn’t flag its own deterioration.
This is where the real risk lives. Not in the tasks that don’t get done on low-energy days, but in the tasks that do.
What you can actually do about it
The solution is not to give everyone unlimited rest days or to lower expectations. It is to design smarter.
The first and simplest thing a leader can do is normalise the conversation. Allow people to say “I’m not at my best today” without it being read as an excuse. That single shift in culture changes what people do with the information. Instead of pushing through a high-stakes task at 40% capacity, they reschedule it. Instead of sending a client proposal they haven’t properly reviewed, they get a colleague to run through it with them or if there is time, they sleep on it.
The second thing is to encourage task-switching on low-energy days rather than task-abandonment. There is almost always productive work that doesn’t require peak cognition – reconnecting with contacts, responding to emails that have been sitting too long, tidying systems, filing, organising. Administrative tasks that create real value without demanding full mental horsepower.
I do this myself. On days when I feel sluggish and know I cannot do my best strategic thinking, I stop forcing it. Instead I reach out to former clients, contacts I haven’t spoken to in a while, connections that deserve a follow-up. It keeps me moving without burning through cognitive resources I don’t have, and more often than not, something useful comes from it.
The third thing is to build recovery into the design of your team’s work. Pacing, breaks, and reflection are not indulgences. They are the mechanism by which peak performance becomes repeatable. A team that never rests is a team that is slowly, invisibly degrading.
The leadership reframe
Managing a team’s energy is not softer than managing their output, it is more sophisticated. It requires a leader to hold two things at once: the reality of deadlines and deliverables, and the reality that the people responsible for those deliverables are biological beings with natural rhythms.
The best leaders don’t demand consistency. They create conditions in which consistency becomes more likely by understanding what depletes their people, building in room to recover, and giving everyone permission to work with their energy rather than against it.
Your team is not underperforming. They are just human. The question is whether your organisation knows how to respond to that.