After the dreary days of winter, summer feels like the time of year when we should jump out of bed every day with a spring in our step, remaining full of vibrancy and energy all day. It can be a surprise, therefore, if you suffer from summer fatigue – but according to one GP, it’s not at all uncommon. Below, Dr. Kaywaan Khan, Private GP from Harley Street’s Hannah London, reveals six surprising reasons you may feel more tired in summer, along with simple ways to manage your energy levels.
Heat Fatigue
In warmer weather, your body uses more energy to cool itself by increasing blood flow to the skin and producing sweat. As a result, you lose fluids and essential salts. These electrolytes are vital for nerve and muscle function, so when levels drop, it can leave you feeling tired and lightheaded. Simple cooling strategies, like running your wrists under cold water, work by cooling circulating blood to help lower your overall body temperature. Staying well hydrated throughout the day is equally important, while applying SPF50+ every two hours can protect against UV exposure and the strain heat places on your body. If fatigue persists despite managing heat exposure, speaking to your GP can rule out any underlying causes, such as anaemia, thyroid imbalances, or vitamin deficiencies.
Poor Sleep Quality
Warm summer nights can leave you feeling tired the next day, even after a full night’s rest. That’s because higher temperatures keep you in lighter, less restorative sleep, making it easier to wake during the night. Heat also disrupts your body’s ability to regulate temperature and, combined with longer daylight hours, can interfere with melatonin levels, increasing the likelihood of disrupted sleep. To avoid poor sleep quality in summer, prioritise a cool-down routine 30 minutes before bed. Create a cooler environment by lowering the room temperature with a fan or open windows, and a darker one using blackout curtains or an eye mask, so your body can cool down properly and stay asleep.
Hay Fever
When summer allergens like pollen enter your body, your immune system releases chemicals such as histamine to “fight” them, even though they're harmless. This reaction causes inflammation throughout your airways, leading to symptoms such as sneezing, congestion, and irritation around the eyes. At the same time, your body uses extra energy to sustain this immune response, which can leave you feeling more tired than usual. Reducing exposure is key, so keep windows closed during high pollen days and use an air purifier to limit indoor allergens. Also, identifying your specific triggers through targeted allergy testing, guided by a GP, can help support more effective long-term management.
Blood Sugar Swings
In summer, sugary drinks and snacks are often consumed more frequently as quick, convenient options to keep you feeling refreshed. When consumed, your blood sugar rises quickly, giving a short burst of energy as they are rapidly absorbed into the bloodstream. Your body then quickly brings those levels back down, which can leave you feeling tired or irritable soon after. This rise and crash in energy can feel even more noticeable in the heat, especially if you’re dehydrated or skipping proper meals. To help keep your energy steady, focus on balancing your blood sugar rather than cutting sugar out completely. Pair sugary snacks with protein or healthy fats (like nuts or yoghurt) to slow the energy release and aim for balanced meals instead of long gaps.
Alcohol Intake
Alcohol intake often increases in summer with more social events, but it can leave you feeling drained by disrupting digestion and increasing dehydration. When you drink, your body prioritises breaking alcohol down in the liver, pulling energy away from other processes like digestion and recovery. This can leave you feeling more fatigued than expected, even the next day. To reduce the impact, hydrate before you start drinking and alternate with water between drinks. You could also swap in lower-alcohol or alcohol-free options to ease the load on your body while still enjoying social occasions.
Travel Disruptions
Your body’s internal clock, also known as your circadian rhythm, controls when you feel alert and when you feel sleepy. It relies on consistent patterns like light exposure, meals, and activity. Travel, even within the same time zone, can shift these cues just enough to make you feel out of sync. As a result, your energy levels can feel off, leaving you more tired than usual during the day. For this reason, I would recommend having a low-demand day after travel where possible, meaning a lighter schedule with fewer commitments. This gives your body time to rest and readjust to changes in environment.
