Exercise and decision-making: training before the meetings that matter

How big is a small effect

Chang's meta-analysis reported an overall effect size of g = 0.097. In plain terms, the average person performed slightly better on cognitive tests after exercise than without it, and the difference was small enough that many individual studies found nothing.

That is not a reason to dismiss it. At the margin, a slightly faster and more accurate mind can matter in a negotiation that turns on one figure or one question. It is a reason not to expect a transformation. The benefit sits on top of preparation and sleep; it does not replace either.

Ludyga's analysis gives a second view. Moderate aerobic exercise had a small effect on the speed of executive-function tasks (g = .35) and on their accuracy (g = .22). Executive function covers planning, switching between tasks and holding back a hasty response, which is close to what a long meeting demands.

Timing: what the studies show, and what they do not

The 2012 meta-analysis reported almost identical effects during exercise (g = 0.101), immediately afterwards (g = 0.108) and after a delay (g = 0.103). The summary of the paper does not identify a moment when the benefit peaks.

You will read elsewhere that the best window opens 11 to 20 minutes after a session of at least 20 minutes. That detail is in the paywalled full text, which we could not verify, so we do not rely on it.

What the evidence does support is that the benefit is present around the end of a session and shortly afterwards, and that it is transient. The 20 minutes the calculator leaves between the end of training and the meeting are there for practical reasons: to cool down, shower, change and read your notes once more. Arriving flushed and late cancels any gain.

Choosing the intensity

Chang and colleagues found that duration, intensity, the type of task and the person's fitness all changed the size of the effect. Larger effects are possible with particular combinations, but the abstract does not say which, so a careful reading points to the middle ground.

Hormone data support the same choice. In a study by Hill and colleagues of 12 trained men, 30 minutes at 40% of maximal oxygen uptake did not raise cortisol. The same duration at 60% raised it by about 40%, and at 80% by about 83%. Cortisol is not a measure of thinking, but the figures show that a very hard session is a different physiological event from a moderate one. The guide to exercise and hormones explains the difference between that acute rise and the longer-term picture.

A simple test keeps you in the right range: you should be able to speak in full sentences, but not sing.

Faster working memory, better mood

Hogan and colleagues tested 144 adults aged 19 to 93. Fifteen minutes of moderate cycling led to faster reaction times on a working-memory task than a control activity, at every age. Participants also reported more high-arousal positive mood, the alert and energised kind.

The measurements were taken immediately after the session. The study does not show how long the effect lasts, so a session at 7 am will not carry a 4 pm board meeting.

Walking when you need ideas

Some meetings need decisions; others need options. Oppezzo and Schwartz found that walking increased creative idea generation in 81% of participants, and that a creative boost remained when they sat down again afterwards. For tasks that require converging on a single correct answer, walking helped only 23% of participants.

These were laboratory experiments, mostly with students. The practical reading is modest: if the next hour is for brainstorming, a brisk walk beforehand, or a walk during a call, is a reasonable choice. See walking meetings and daily steps.

A pre-meeting session, step by step

1. Enter the meeting time and the length of session you can afford in the calculator below.
2. Start with five minutes of easy movement: brisk walking, a gentle cycle or mobility work.
3. Hold a moderate effort for most of the session. Cycling, a treadmill at a brisk incline, or a light circuit all work.
4. Finish with three to five minutes of easy movement so that your heart rate settles.
5. Shower, change and spend the last few minutes on the one point you most need to make.

In a hotel, a bodyweight circuit at a conversational pace does the same job. See the hotel room workout.

Who stands to gain most

In Ludyga's meta-analysis, aerobic fitness did not change the size of the benefit: low-fit and high-fit people improved in a similar way. You do not need to be an athlete to use it.

The largest effects were found in preadolescent children (g = .54) and in older adults (g = .67). For adults in mid-career, the effect is probably smaller than in those groups. That is another reason to see a pre-meeting session as a nudge rather than a strategy.

The longer view

The US umbrella review by Erickson and colleagues rated as strong the evidence that single sessions of moderate to vigorous activity bring a transient benefit to cognition after exercise. The World Health Organization lists reducing cognitive decline, improving memory and boosting brain health among the benefits of regular activity.

The short-term lift is the visible part. The quieter gains come from training most weeks of the year, sleeping well and keeping fit into later decades, which the guide to exercise and business performance puts in context.

If you are new to exercise or have any cardiovascular symptoms, keep sessions before meetings moderate and build up gradually. See a doctor for chest pain, faintness or palpitations.

A coach who knows your diary can place these sessions for you; you can start with the Club.