Cystitis, a type of urinary tract infection targeting the bladder, becomes more common during summer, experts say. The condition, which often causes a stinging sensation, frequent urination, dark or smelly urine, and stomach pain, affects up to 60% of women at least once in their lifetime, with one in three experiencing recurrent episodes.
Why summer increases risk
Dehydration is a key factor. Dr Babak Ashrafi, GP for Superdrug online doctor, explains: "When we’re dehydrated, urine becomes more concentrated, which can irritate the bladder and increase the risk of infections developing." Pharmacist Noel Wicks adds that unpredictable British summer weather creates a "perfect storm" for cystitis. "During summer months, temperatures fluctuate significantly. Even in a single day, we can jump from cloudy, colder days to warm, hot temperatures and mini heatwaves. These shifts can impact hydration levels, immune function and bacterial growth," he says.
Sweating also plays a role. "Naturally, we will sweat more, and this includes in the groin area, which can encourage bacterial growth," Wicks notes. "Warm, moist environments encourage bacterial growth… even small environmental changes can upset the delicate balance of bacteria around the urinary tract."
Reddit users share experiences
On Reddit, users have noted summer flares. @SweetRollsandSkooma wrote: "I’ve noticed over the last couple of years that summertime is when I get the most flares." @hantricote said the "heat certainly seems to play a role for me," while @Rare_Dog_4724 described the heat as wreaking "unbearable" havoc on symptoms, adding: "I love the winter. My bladder doesn’t flare as much because it’s cold and the sweat is non-existent."
Prevention tips from the NHS
The NHS advises: wiping from front to back, keeping genitals clean and dry, drinking plenty of water, washing the skin around the vagina with water before and after sex, weeing after sex, and wearing cotton underwear.
Summer activities and sex
Swimming, walking, and gym sessions can increase risk due to tight clothing trapping moisture or damp swimwear not changed immediately. Dr Ashrafi notes that holding in urine during travel or festivals and consuming alcohol or caffeine can contribute to dehydration and bladder irritation. Sex-induced cystitis accounts for roughly 60% of recurrent cases, with movement during sex moving bacteria into the bladder. Dr Catherine Hood previously told Metro: "We may enjoy more sexual activity in the summer, with sex from behind being especially bad for women with recurring cystitis."
The article also notes that thrush and bacterial vaginosis (BV) are especially prevalent during warm weather, disrupting the balance down below.
