Why December feels so hard to lead: ‘juggling mode’ and its impact

Everyone feels tired in December, yes, but leaders feel it differently. As well as managing their own workload, they’re absorbing the fragmentation of everyone else’s. They’re the ones bridging gaps, smoothing issues, resetting expectations and catching what falls between the cracks. 

That’s why the month feels heavier for leaders even when the workload hasn’t changed. All the stopping, starting, switching and re-loading of your brain takes more out of you than any single task on your list. 

Recent research backs this up, studies summarised by the American Psychological Association show that shifting between tasks significantly reduces productivity and increases the mental “reset time” required to get back into focus. 

The leadership juggling load 

Leadership is already a high-cognitive-load job, and instead of long stretches of focused time, December becomes a month of: 

• short, sharp decisions 

• half-conversations 

• interrupted thinking 

• reactive firefighting 

• last-minute approvals 

• shifting deadlines 

• people dipping in and out around annual leave (or off sick!) 

And the impact is measurable; studies show that shifting between tasks significantly reduces productivity and increases what researchers call “attention residue” - the lingering cognitive drag after switching. A 2023 study on dual-task coordination found that frequent switching leads to slower thinking, reduced accuracy, and greater mental fatigue. 

Why December amplifies the juggling 

1) People aren’t around consistently  

Some are on leave, some are about to go on leave, some are off sick, some are mentally half on/half off. Leaders step in to fill the gaps, answering questions, smoothing issues, and picking up loose ends. Each “quick interaction” comes with an invisible cognitive price tag.

2) The month is short, but expectations aren’t  

Despite being effectively a three-week month, December still carries full-month expectations: project closures, budget signoffs, year-end reporting, and pre-holiday decisions. This creates workload compression, a pattern shown to increase time pressure, fatigue, and perceived cognitive load. A 2024 study in the European Journal of Work and Organisational Psychology found that compressed work cycles significantly heighten stress and reduce focus. 

3) Emotional labour increases 

Leaders carry the emotional tone of the business - and emotional work is still work. Family logistics, performance reviews, team morale, personal pressures: December loads leaders with people-energy, not just task-energy. 

4) The pressure to finish well and instantly switch off 

Culturally, December demands a perfect duality: 

“Push hard to the end… and then totally relax.” But the reality is that very few leaders get both. December follows a predictable arc: 

Phase 1: High clarity Leaders begin the month focused, energised and in control. 

Phase 2: Rising fragmentation Availability becomes uneven; interruptions multiply, and leaders switch between more pieces of work, more often. 

Phase 3: Cognitive drag By the final stretch of December, leaders are carrying the cumulative effect of fragmented thinking. Focus feels harder to access; decisions take longer, and priorities blur around the edges. A 2023 mechanistic review showed that sustained cognitive load from constant task disruption creates measurable “cognitive drag” - slower thinking, reduced accuracy and higher mental fatigue. 

Why this matters for January 

Leadership energy sets team tempo, meaning that December dip cascades through everyone. When leaders limp into the break, teams can often start January in recovery mode. When they start the break intentionally, teams start faster, cleaner, and more confidently. This is why simply “pushing through” December often backfires, and the repercussions show up not in December, but in January. 

So, what should leaders do with this insight? 

The point of this blog isn’t to provide the playbook; that’s what our December webinar is for (see more details below). It’s to help you recognise that what you’re experiencing is a pattern, not a personal failing. Understanding the shape of December allows you to lead with intention rather than frustration, and it helps you protect your energy, set expectations differently, and prepare for January from a place of clarity rather than depletion. 

Join our conversation!  

If this resonates, Gareth Greppellini and Gary Gamp will be sharing the practical moves leaders can take to finish 2025 well - and start 2026 with clarity, energy and direction. 

10th December  14.00–14.45 GMT 

Register here.