The summer is here, with longer days and much more sunshine. Not many people stop to think about the physical and mental effects of the hot weather though, but it’s a fascinating area.
Most of us feel good in the sun and there are real biological reasons why this happens. For example, our skin absorbs UVB rays and makes a precursor to active vitamin D, which is then activated in the liver and kidneys. This “vitamin” is actually a hormone that can help immunity, bone health, and support hormones. In fact studies show that people who live closer to the equator tend to have lower rates of autoimmune disease[1]!
It’s not just about vitamin D though; UVA and UVB rays stimulate nitric oxide which lowers blood pressure and enhances circulation and oxygen delivery to our tissues. It’s been shown that systolic blood pressure drops with UV exposure in both healthy people and those with chronic conditions[2]. It may not be enough of a drop to get you off blood pressure medications if you’re on them, but it is significant.
Sunshine in the morning can anchor our circadian rhythm, which can improve sleep at night. It can also boost testosterone levels and serotonin, all of which can hugely improve mood and the feeling of wellbeing. Studies show there is a seasonal effect on mood and it may be partly mediated by the hormonal effect[3]. What’s more, UV light can trigger the release of something called β-endorphin in skin, which is a natural painkiller. This may be one mechanism by which many people report improvement in their aches and pains when it’s summer or they go on holiday.
Most people think of sunshine as just for vitamin D, but the above benefits may explain why popping a vitamin D pill doesn’t seem to replicate the same health benefits in studies; vitamin D status may simply be an indicator of how much sun (and therefore nitric oxide, beta endorphin, serotonin etc) you are getting.
Warmer weather also means more opportunity to exercise outdoors in nature, which is a huge boost for mental wellbeing. Just seeing nature can lower cortisol, however plant bioactive compounds called phytocides also interact with our bodies to reduce stress hormones and boost immunity[4]. Summer is also a good time to gather for social events such as picnics, festivals or outdoor sports; community is vital to wellbeing.
The key is not overdoing it. It’s very important not to get sunburn as this can contribute to skin cancer, so hats, long clothing and sunscreen may be necessary if you’re outdoors a lot, and especially if outdoors between 11am-3pm when the UV rays are strongest. Try to get outdoors in the morning and evening in particular especially as these times help entrain the circadian rhythm.
Another thing to be mindful of are heatwaves; we’ve already had a few! Avoiding overheating and too much sun exposure is important, as is dehydration. If you’re sweating a lot, you need to be drinking plenty of water, and you may find some extra electrolytes help (as you lose salt, magnesium and potassium through sweat). It’s important to listen to your body, any headaches, nausea, fast heart rate or muscle cramps might indicate heat stroke, and mild discomfort may suggest it’s time to find somewhere cool and hydrate.
Many women struggle to tell if they’re having menopausal hot flashes when it’s very hot, and thyroid issues can also affect how you respond to the heat. The oestrogen fluctuations during perimenopause can affect the brain’s thermoregulation centre, a kind of “thermostat”, essentially making it more sensitive to even minor temperature change. In the summer heat this can worsen or trigger hot flashes where one can get sudden feelings of overheating, night sweats or excess sweating, as the body attempts to cool itself.
With thyroid issues, having an overactive thyroid can also cause the sensation of feeling too hot as the thyroid hormones speed up metabolism. The opposite happens when the thyroid is underactive; feeling colder than the outside temperature would predict. If you are feeling excessively hot, and are not sure it’s entirely due to the weather (or similarly feel colder than others around you), it is worth seeing a doctor for a full workup, which may include hormonal and thyroid tests.
The bottom line, enjoy the sunshine’s benefits while keeping skin safe, stay hydrated, and be aware of hormonal effects with the hot weather.
By Dr Reamika West, a specialist in integrative women’s health and bioidentical hormone balancing for the Marion Gluck Clinic
Sources:
[1] https://pmc.ncbi.nlm.nih.gov/articles/PMC12243313/
[2] https://pubmed.ncbi.nlm.nih.gov/19797169/ https://pubmed.ncbi.nlm.nih.gov/32106744/
