Around this time in the year, I notice the same thing in myself, in patients, and so many people around me – Winter starts to fade, the snow begins to melt, the days get a little longer – and yet… we don’t feel as good as we think we should.
Our energy is still low, sleep is off, the scale has crept up, digestion feels off, and moods are a little heavier than normal. What does the research show? It is a winter physiology shift.
Just like how bears hibernate, the human body shifts as well in the winter months impacting hormones, metabolism, brain chemistry, and energy.
What Happens to the Body During Winter
There are very real, very measurable changes that happen in the body during the winter months due to reduced sunlight, cold temperatures, and changes in activity levels.
One of the biggest changes is vitamin D depletion.
Vitamin D levels naturally follow a seasonal pattern — they peak in late summer and reach their lowest point in late winter, typically around February, because vitamin D production depends on sun exposure. During winter months at northern latitudes, the sun is simply not strong enough for your skin to make adequate vitamin D, even if you are outside. Studies show that 33–58% of people are vitamin D deficient during winter, even if they are supplementing. Low vitamin D is associated with immune dysfunction, bone health issues, cardiovascular disease, autoimmune conditions, and even certain cancers.
Winter also shifts the immune system into a more pro-inflammatory state. Research shows that inflammatory markers like C-reactive protein and IL-6 increase during winter months, and over 4,000 genes in white blood cells actually change their seasonal expression. While some of this may be protective, this winter inflammatory pattern is also linked to higher rates of cardiovascular disease, autoimmune flares, and mood disorders — all of which peak during winter.
Then there is the effect of reduced daylight on mood and brain function. Seasonal Affective Disorder is the extreme version, but even in people without SAD, reduced daylight exposure is associated with more depressive symptoms, more fatigue, increased appetite, weight gain, and sleep disturbances. Just getting one hour of daylight per day has been associated with significantly lower rates of depressive symptoms.
Winter also puts more stress on the cardiovascular system. Cold temperatures trigger vasoconstriction and activate the sympathetic nervous system, which raises blood pressure — especially in the morning. This is one reason heart attacks, strokes, and heart failure are more common during winter months.
Metabolically, the body also adapts to cold. Brown fat activity increases to generate heat, which changes energy expenditure and metabolic patterns. Some researchers have even noted similarities between winter physiology and mild hibernation patterns in animals — including shifts in nervous system activity and energy conservation.
And on top of all of this, most people are:
- Moving less
- Spending more time indoors
- Getting less sunlight
- Eating heavier foods
- Sleeping differently
So by the time we reach the end of winter, many people are walking around with:
- Low vitamin D
- Higher inflammation
- Slower metabolism
- More body fat
- Lower energy
- Worse sleep
- Higher blood pressure
- More mood changes
- Sluggish digestion
In other words, the body is still in winter mode — but the calendar says it’s spring.
How do we shift the body out of Winter mode?
For those who are feeling the winter effect – puffy, inflamed, heavy, slow, increased cravings, disrupted sleep – that is your body telling you it is still stuck in winter mode and needs support to transition with the season.
Spring is naturally a season of reset, drainage, movement, and metabolic activation — historically this is when humans moved more, ate lighter foods and bitter greens that support the liver and digestion, and spent more time in the sun. But modern life doesn’t naturally support that transition. Instead many people try to force weight loss, cut calories, over-exercise, or do extreme cleanses, which often makes metabolism, hormones, and energy worse.
The good news, is that there are simple and effective habits that help shift our body out of winter mode – habits that focus on lowering inflammation, improving digestion, stabilizing blood sugar, resetting circadian rhythm, and restarting our metabolism.
This is exactly why I created the 14 day Detox Reset – to help our body readjust when it needs some extra support and structure to reset.
We will be launching our group 14 Day Spring Challenge – Detox & Reset April 16th. I will be doing it alongside you because I need this reset as well.
I hope you’ll join us.
Learn more about the 14 Day Spring Challenge here.