Are you feeling fatigued, dull, flabby and saggy? The season affects more than your mood.
Dr. Debbie Smrz, ND
No sun, cold temperature, an abundance of chocolate and cookies from Christmas leave us in this position every January, so if you’re feeling this way you’re not alone. The good news is, it’s unlikely you gained as much as you think you did. Studies show that most people gain only a pound or 2 of actual weight, and easily lose it when they get back into a routine.
One reason that can cause long term weight gain over the holidays in sleep deprivation. We now know that those that don’t sleep enough tend to be hungrier, consume more calories, and exercise less. Furthermore, we then revenge eat or self sabotage. Well, I messed up and ate one cookie, might as well eat them all. Easily falling into a spiral of lack of sleep, low motivation, feeling fatigue and weight gain.
Surprisingly, your hormones are affected by the weather as well. Hormones control stress, growth, metabolism and reproduction, and a 2020 study shows that each hormone is affected by the season, with thyroid and saliva cortisol show seasonal changes on the order of 10%.
Your body is constantly trying to maintain homeostasis, such that each organ, function and system has a set point it is trying to maintain. This is why when you manage weight you so easily gain it back again, your cells are trying to get back to their previous set point. (You can maintain your new weight by maintaining your new weight for a certain length of time, I find it to be at least 3-6 months in most people).
Organisms can change their set point for any or all functions with the season. This study raises the possibility of an internal seasonal clock in humans that provides a high endocrine set-point for reproduction, growth, metabolism and stress adaptation in winter-spring.
So if you’re noticing a change of attitude, sleep, energy and feeling fatigue over the winter months, it might be more to it than lack of motivation to get outside. This is also an extremely good reason why variations in blood values can be seen in different seasons, and why using the same lab, at the same time of day in the same season is a way to truly compare blood work.
Seasonality of hypothalamic-pituitary axes hormones from Clalit medical records.(A) HPA axis with pituitary hormone ACTH and effector hormone cortisol. (B) Thyroid axis with pituitary hormone TSH (thyroid stimulating hormone) and effector hormones T4, with its derivative T3. (C) Sex axis with pituitary hormones FSH (follicular stimulating hormone) and LH (luteinizing hormone), and effector hormones testosterone and estradiol. (D) Growth axis with pituitary hormone GH (growth hormone) and effector hormone IGF1, (E) lactation pathway with pituitary hormone PRL (prolactin) that controls breast milk production. Each panel indicates the number of tests n, zero-mean cosinor model (gray line) and R2 where significant (, ns – not significant), with first or second order model selected by Aikake criterion (second-order model is indicated by ^ above R). Vertical dashed lines indicate solstices Dec 21 and Jun21. You can book an appointment for more information
Avichai Tendler, Alon Bar, Netta Mendelsohn-Cohen, Omer Karin, Yael Korem, Lior Maimon, Tomer Milo, Moriya Raz, Avi Mayo, Amos Tanay, Uri Alon
bioRxiv 2020.02.13.947366; doi: https://doi.org/10.1101/2020.02.13.947366