How much talent are you ready to lose?
Every year, January becomes a litmus test for company culture.
From the outside, it looks like people “suddenly” break after the holidays. In reality, they just stop holding it together.
I was once part of that sad statistic myself and didn’t return to my job after the Christmas break. Today, I’ve pulled together what we know about why this happens, what’s going on in the brain, and what it means in real numbers for Dutch employers.
1. Peak of burnout-related sick leave happens in January
Dutch occupational health providers ArboNed and HumanCapitalCare (together covering around 1 million employees) reported that in January 2025 the number of sick reports reached the highest level in four years. The average sickness absence rate jumped from 4.8% in December 2024 to 5.1% in January 2025.
Earlier analyses from the same group show that the Monday after the Christmas holidays is the day with the highest number of sickness reports that later turn out to be long-term absence, often driven by stress-related problems that have built up gradually.
So while “Blue Monday” is scientifically solid concept, January is objectively a peak month for sickness absence and the first weeks are especially risky for long-term cases, with work stress and burnout making up a growing share of that picture.
2. Why does this happen exactly then?
Most people don’t collapse during the race. They collapse just after.
Towards the end of the year, we keep telling ourselves:
“If I just push a bit harder, it’s going to be alright.”
“I’ll just make it to Christmas and then I’ll rest.”
We believe that this project, this quarter, this promotion will finally change things. Fueled by that hope, the brain is willing to invest huge amounts of energy as long as it expects a meaningful reward.
But then December comes and it becomes clear that Santa has forgotten about us. Nothing really changes in the end: the promotion isn’t coming, the workload won’t ease, the culture stays the same.
Our internal effort–reward system runs the numbers and quietly concludes:
“This is not worth it.”
That is the moment the brain stops believing that “just pushing a bit longer” will fix it. People don’t just feel tired. They slide into what the WHO officially calls burnout – a syndrome resulting from chronic workplace stress that has not been successfully managed, characterised by exhaustion, mental distance or cynicism, and reduced effectiveness.
From the outside, it may look like they “suddenly” crash after the holidays. But in reality, inside it has been building up for months or years.
3. What’s going on in the brain: the effort–reward imbalance
There is a well-studied model in occupational health: Effort–Reward Imbalance (ERI), developed by Johannes Siegrist in 1996.
In simple terms, our brain constantly (and subconsciously) calculates what is worth pursuing and what is not. It keeps investing energy in a goal as long as the rewards seem to match the effort: pay, recognition, learning, career progress, more autonomy, a sense of impact. But when the effort stays high and the rewards stay low, the system reads this as non-reciprocity:
“I give a lot, I get little back.”
That’s when the brain starts cutting the energy expenses to something that presumably doesn’t worth the investment.
At the same time, chronic activation of the stress system creates allostatic load – the classic “wear and tear” on the body from long-term stress.
A growing body of research shows that burnout is associated with higher allostatic load and physiological dysregulation of the stress system where it keep itself active even in the absence of threat.
So in January these two curves meet:
Motivation drops because the effort–reward calculation no longer makes sense.
The body can’t compensate anymore because of accumulated allostatic load.
From the outside it seems sudden:
“She was fine before Christmas, and now she’s on sick leave.”
From the inside, the system has been running in overdraft for a very long time.
4. The math: how many will leave and what it costs
Let’s zoom into Dutch numbers using the new TNO Werkstress 2025 factsheet (NEA 2024 / NEA 2023 data).
According to TNO:
1.7 million employees in the Netherlands have burnout complaints, it’s about 20% of all employees.
3.3% of employees say a doctor has diagnosed them with the occupational disease overspanning / burnout.
In a company of 100 people, that roughly translates to:
20 people with serious burnout complaints (still at work, but struggling).
3 people who either already have, or are very close to having, a formal burnout diagnosis.
And if having “a few” employees with a burnout doesn’t sound dramatic let’s look at the consequences
The same TNO factsheet (NEA 2023 for cost data) show that in the Netherlands alone:
Employees take 14.3 million sick days in one year were due to psychosocial workload (work stress, high demands, conflict, unwanted behaviour). With 10.3 million days were directly linked to high workload.
Total sickness absence costs due to psychosocial workload are estimated at about €4.9 billion per year.
The average cost per employee with absence due is about €14,500.
Now scale this down to a 100-employee company:
If just 3 people go into long-term stress-related sickness absence, you’re quickly at about €43,500 in direct absence costs alone (3 × €14,500 = €43,500), before counting replacement, recruitment, and lost productivity, which many HR sources estimate at around half to twice an annual salary per employee.
And all of that is before we factor in the people who don’t go on sick leave, but:
quietly reduce their effort (quiet quitting)
stop going the extra mile (disengagement)
or start looking for another job, as burned-out employees are 2.6 times more likely to be actively seeking a different job (Gallup).
5. What you can still do now:
Here’s the good news:
For many high performers, it’s not too late.
At any time, and especially before the year ends managers can do a lot with simple human actions.
1) Give real, specific feedback (not just “good job”)
High performers often need to hear:
What exactly they did well:
“You handled that client escalation calmly and saved the relationship.”Where their work had impact:
“Your restructuring of this process brought us 20% increase in revenue.”
This gives their brain the reward signal it has been missing.
2) Say “thank you” and name the cost
Instead of a generic “Thanks everyone”.
Try:
“I see you’ve carried a heavy load this quarter.”
“I know you worked late multiple nights to get this release out.”
When leaders name the cost, people feel seen. That alone reduces the sense of unfairness in the effort–reward imbalance.
3) Talk openly about workload and make improvements
Even if you can’t fix everything before year-end, make it clear:
What you will stop, delay or de-scope.
What you will hire / automate / reorganise in Q1.
For example:
“We’re not adding new big projects in January. The priority is finishing X and stabilising Y. I’ll personally shield you from extra requests until we review the workload together.”
Promise one or two specific things and follow through.
4) Ask for their opinion, especially on how you manage
High performers usually have sharp insights about what’s broken, but many have stopped sharing because “nothing changes”.
Ask questions like:
“If you could change just one thing about how we work that would make your life better, what would it be?”
“Where do you feel your effort and the reward are most out of balance right now?”
Then act on at least one suggestion quickly, even if it’s small. That restores a sense of trust and reciprocity.
5) Make it safe to open up before they crash
Say this explicitly:
“If you notice you're depleted, I’d rather you talk to me now than disappear for three months in February. We’ll find a way together.”
Give people permission to:
redistribute work short-term,
adjust deadlines,
take a proper break without guilt.
You can even connect it directly to business outcomes:
“Protecting your long-term capacity matters more than squeezing out one more week of self-sacrifice.”
Closing thought
While it's impossible to predict the scale of resignation and long-term leaves in the beginning of a year in any given company, the dynamic is predictable: if someone is already close to the edge, January is when the system likely gives up.
So even amidst the hustle and stress of the end of the year, it's worth pausing and asking the really important question for this month:
How much of that talent are you willing to lose?
And if losing high performers is not your intention, it's time to do something to save them.