summer slump? why heat affects your energy.

Summer Slump? Why Heat Affects Your Energy

Summer brings warm sunshine, but the heat can have a surprising impact on your body. It's not just the rising temperatures that are at play - heat can disrupt your gut health, which in turn affects your digestion and energy.

The Link Between Heat, Your Gut and Energy Levels

When temperatures rise, your body releases cortisol, the stress hormone, to help manage the heat. While cortisol is essential for handling stress, too much of it can disrupt your gut’s natural rhythm. Elevated cortisol interacts with gut cells such as immune cells and epithelial cells (which form the gut lining), throwing off your balance of good and bad bacteria.

Cortisol can speed up or slow down your digestion, leading to symptoms like bloating, constipation, or even diarrhoea that can further leave you feeling sluggish or fatigued, draining your energy.

The Gut–Brain Connection: How Heat Affects Your Mood

Your gut and brain are constantly communicating through the gut-brain axis, which helps regulate digestion, mood, and energy levels. Heat stress raising cortisol levels can interfere with this system, affecting both your gut and your energy.

High temperatures activate the hypothalamic–pituitary–adrenal (HPA) axis, further raising stress hormones like cortisol. This, along with inflammation, can impact your gut microbiota and digestive function, leading to mood swings, fatigue, and mental fog. So, when the heat affects your gut, it's not just your digestion that suffers but also your energy and mental clarity take a hit.

How Heat Affects Your Gut Microbiome

Heat stress alters the balance of your gut microbiome, which can have a significant impact on your energy levels. Research shows that heat stress can:

• Increase opportunistic bacteria like Campylobacterales and Megasphaera, which disrupt gut health.

• Decrease beneficial bacteria like Lactobacillus murinus, which help maintain gut balance and support digestion.

• Shift metabolic pathways, impairing your body’s ability to process nutrients and produce energy.

When your microbiome is out of balance, nutrient absorption is hindered, leaving your body with less fuel and contributing to feelings of fatigue and sluggishness.

Leaky Gut: How Heat Affects Your Energy

Heat stress can also lead to a condition known as "leaky gut," where the gut lining becomes more permeable. This allows toxins and harmful bacteria to enter the bloodstream, triggering an immune response and increasing inflammation.

The impact on your energy is significant as your body diverts resources to combat inflammation, draining your energy reserves. Symptoms like bloating, fatigue, brain fog, and low energy are signs of this imbalance. Without proper nutrient absorption, your body lacks the fuel it needs to maintain optimal energy levels.

Tips for When It’s Hot

Here’s how you can protect your gut during hot weather:

• Dehydration worsens digestion and contributes to fatigue. Drink plenty of water and electrolyte-rich fluids to stay hydrated and energised.
  

• Opt for hydrating fruits, veggies, and salads to keep your digestion light and provide your body with nutrients without overloading your system.

• Avoid alcohol as they can irritate your gut, especially in the heat, and leave you feeling sluggish.
  

• Heat can drain your energy, so make sure to rest in the shade or indoors to conserve your energy and support digestion.
  

• Stress management techniques like meditation or breathing exercises can calm the HPA axis, support gut function, and stabilise your energy levels.

References

Bennett, C. J., Henry, R., Snipe, R. M. J., & Costa, R. J. S. (2020). Is the gut microbiota bacterial abundance and composition associated with intestinal epithelial injury, systemic inflammatory profile, and gastrointestinal symptoms in response to exertional-heat stress? Journal of Science and Medicine in Sport, 23(12), 1141–1153. https://doi.org/10.1016/j.jsams.2020.06.002 

Huus, K. E., & Ley, R. E. (2021). Blowing hot and cold: Body temperature and the microbiome. mSystems, 6(5), e00707-21. https://doi.org/10.1128/mSystems.00707-21
Xia, Z., Huang, L., Yin, P., Liu, F., Liu, Y., Zhang, Z., Lin, J., Zou, W., & Li, C. (2019). L-Arginine alleviates heat stress-induced intestinal epithelial barrier damage by promoting expression of tight junction proteins via the AMPK pathway. Molecular Biology Reports, 46(6), 6435–6451. https://doi.org/10.1007/s11033-019-05090-1 

Rony, M. K. K., & Alamgir, H. M. (2023). High temperatures on mental health: Recognizing the association and the need for proactive strategies—A perspective. Health Science Reports, 6(12), e1729. https://doi.org/10.1002/hsr2.1729