Chest and critical care specialist Dr. Ooi Hean recently warned that during the hot summer months, leaving bottled water in plastic containers under prolonged sunlight can accelerate the release of Bisphenol A (BPA) and other chemicals. Long-term exposure to these substances may lower sperm quality in men and interfere with ovulation in women.
Dr. Ooi explained on his Facebook page “Dr. Ooi Hean” that many people buy bottled water at noon, drink a few sips, then leave it in the car under the blazing sun. When they return, the bottle is covered in condensation, the water feels like it’s been in a hot spring, and they think, “It’s just hot water, no big deal, right?” But in reality, that sip might mean you’re drinking plastic.
In his “Reading Notes”, Dr. Ooi elaborated that plastic bottles (PET or polycarbonate) can loosen or even break down at high temperatures, releasing BPA into the water. Citing a Harvard human trial, he noted that 77 students first used stainless steel bottles for a one-week “washout” period, then switched to polycarbonate bottles for cold drinks over the next week. Results showed their urinary BPA geometric mean increased from 1.2 μg/g creatinine to 2.0 μg/g creatinine—a jump of 69% (p < 0.0001)—proving that polycarbonate bottles significantly raise BPA levels in the body.
BPA is classified as an endocrine disruptor. Prolonged exposure can lower sperm quality, disrupt female ovulation, increase risks of obesity and type 2 diabetes, raise chances of high blood pressure and coronary heart disease, and in pregnant women, potentially affect fetal brain and behavioral development.
Dr. Ooi offered four tips to avoid “drinking plastic” in summer:
- Never leave bottled water in the car, as temperatures can exceed 60°C.
- Use glass or stainless steel bottles, which are heat-resistant and reusable.
- Choose bottles labeled “BPA-Free”.
- Do not reuse disposable PET bottles for hot water.
Finally, Dr. Ooi reminded everyone to avoid storing bottled water in high-heat environments. Switching to safe, heat-resistant containers is a simple yet effective way to protect yourself—because safeguarding every sip is safeguarding your health.
