June marks the beginning of meteorological summer, but after last week's heatwave, this week is set to bring much cooler and wetter conditions. The Met Office has predicted spells of rain, possible thunderstorms, and strengthening winds through much of the week. These dramatic weather changes can leave many people feeling unsettled, both mentally and physically.
Why Temperature Swings Are Challenging
Dr Lucy Hooper, a London-based GP and co-founder of Coyne Medical, explains that frequent temperature swings make it difficult for the body to acclimatise. "In Britain, we get hot spells followed by cold weather, so we don't get the chance to fully acclimatise," she says. "In hotter countries, people adjust their behaviour and fluid intake, and their bodies learn to adjust. But in the UK, we experience very sudden changes, so we don't build that tolerance. It takes around seven to 14 days to acclimatise to hotter climates, whereas we see weather changes on a day-to-day basis."
Hooper warns that increasingly unpredictable summers, with alternating heat and cool weather, may be more disruptive than sustained warm spells. "It looks like we're going to have lots of summers where it's hot, cold, hot and cold again, which is potentially more destabilising than having four to six weeks of really hot weather," she says. "Your body is continually trying to find a new balance, and then everything changes again."
Four Ways Fluctuating Temperatures Affect You
1. Sleep
"Warm weather has a massive impact on our body, and one of the biggest impacts is on our sleep," says Hooper. "Even moderate increases in temperature can make us lose out on restorative sleep stages, which can have a big impact on overall health and wellbeing."
2. Mood
Seasonal Affective Disorder (SAD) is often associated with winter, but it can also affect people in summer. "Lots of data shows that some people experience SAD in the summer," says Hooper. "Rising temperatures can also impact aggression. Many people become more stressed in the heat, and there seems to be a link with rising temperatures and increasing crime rates and domestic violence rates." Changes in routine also play a role: "When there are extremes of weather, we are more likely to cancel plans and not go outside or exercise, which can impact our wellbeing."
3. Immune System
"Heat can definitely impact the immune system," says Hooper. "You get more inflammatory signals and stress responses in the body. If that continues, the body often stops responding to those stress signals to conserve energy. That's why we think that with a lot of heat exposure, your immune system might not respond as well as usual. When the weather gets cooler, there's less stress on the body, giving an opportunity for the immune system to recover, but responses to heat stress don't happen instantly. It takes time for our body to recover, and the impact is still felt for a while."
4. Brain Fog
"Hormone changes, such as cortisol and serotonin, in hot weather can affect brain function in terms of memory, decision-making, and energy levels," says Hooper. "Even once the temperature drops, people still seem to have some response. Brain function doesn't go back to normal baseline straight away. This is especially the case in middle-aged and older adults, where there seems to be prolonged dysfunction of brain and neurological function."
5. Cardiovascular System
"In hot weather, your heart rate goes up, blood pumps more, and there is more blood flow, which can put strain on the heart," says Hooper. "Although that should be relieved when temperatures fall, it doesn't change immediately, and some strain may still be felt after hot spells."
Tips to Counteract These Effects
"Good sleep is a big thing to prioritise," advises Hooper. "Do what you can practically to help, such as keeping your bedroom cool." She also recommends thinking about how temperature fluctuations might be impacting your wellbeing. "If you are feeling more stressed, irritable, or angry than usual, consider self-care activities to prevent negative impacts on your relationships." Staying hydrated is crucial: "Keeping hydrated is a simple but important thing we can do." Finally, "make sure you are still getting out and seeing people. Keeping to your regular routines as much as possible can also help you stay feeling well."
