On a typical slightly humid hot day in NYC, I was due for dinner at L’Avenue Saks. To feel a bit coolness, The Chalet-level terrace awaits the sun to tuck itself behind Rockefeller Center. Until then, the only thing I could think about was of a cold tall glass of anything. Not even the new perfect-everything Gucci sandals on Saks’ expansive shoe floor could hold my interest. I was feeling an appreciable mix of dehydration, heat and inertia.

I switched up my plans to an earlier dinner. I spot the hibiscus mocktail on the menu and do not need to think twice. The Sour Flower had a mix of all the holistic goodies needed for that kind of day- hibiscus, tarragon and soda. It was a rose pink and stacked with perfect cubes of ice. The fizzy bubbles floated up the glass and with every pop breathed life into the near-mugginess.

During my leisurely senior-timed dinner, I thought about why Ayurveda and TCM shun iced or cold water. It’s a “you can’t sit with us” type of thing. Even my primary-schooled grandmother thinks ice in drinks are taboo.

Apparently, lower temperature beverages, especially iced, slow down digestion. Digestive issues, according to traditional medicine, is the root of all health issues. It’s not just these medical philosophies. An 1859 medical journal warned against drinking iced water.

“It is known by... scientific men, that the process of digestion in the stomach is arrested. That process is not resumed, until enough heat has been taken from the general system, to raise the water from thirty-two or more degrees.”

— Hall's Journal of Health

In contrast, sports research findings show that cold water boosts performance without cooling muscle temperature. It might also be that eating ice increases digestion.

Because Ayurveda and TCM have other remedies for dehydration and overheating, they suggest to have room temperature drinks during the Summer. No thanks, says the Summer heat wave.

the $cience

We’re not walking around with thermometers testing our drinks while outdoor dining this Summer, so here is a breakdown:

iced refrigerator water = 41 degrees Fahrenheit

cold tap water = 60 degrees Fahrenheit

room temperature water = 78 degrees Fahrenheit

Research findings indicate ice water of less than 30 degrees Fahrenheit is good before and during long workouts in the heat. Thirty minutes of HIIT training showed improved performance without decreasing muscle temperature. The “slurry” contained a Gatorade-type solution of carbohydrates and electrolytes, so it is more of a sports drink than simply iced water. The same mix warmed up did not produce the same results. Though metabolism and digestion were not measured, the ice-processing gut cools the internal core temperature. Ice may burn calories because the work (energy) it takes for the GI tract to increase body temperature in its attempt to reach homeostasis.

Though cold carbonated water will not cool you down, it will make you less lethargic. In two 2022 studies, cold Asahi carbonated water was found to decrease lethargy and dizziness without changing perceived hotness or thermoregulation. One Asahi-funded study showed their cold carbonated water decreased dizziness in older people who spent long periods sitting or sleeping (orthostatic hypotension). Carbonation apparently raises blood pressure to correct both conditions. Not a lot of cold water is needed to increase blood pressure to resolve sleepiness and dizziness, so it might not aggravate Pitta-related high-blood pressure.

There are cases where people should not have any cold or iced beverages. The inability to digest properly, like esophageal dysfunction (achalasia) and Kapha conditions, is a sign to stick to hot or room temperature beverages.

bottom line

Regular cold water and iced water will drop internal core temperature and increase feeling cooler during a heat wave. The former is noted during intense physical activity, so maybe a lot of iced water is not necessary for ladies who lunch or Chipotle boys. Sugary drinks, cold or not, are known to not support good health of teeth, metabolism and brain health. If you feel the need for cold water or drinks and your doctor does not disagree, then opt for healthy choices.

Refreshing drinks with digestive-friendly herbs may minimize possible negative effects. Think of that hibiscus Sour Flower or a cool peppermint tea. Research on hibiscus found that it acts as an anti-inflammatory in the gut. Ayurveda purports that hibiscus is beneficial for Pitta, but can aggravate Vata conditions. Found in peppermint oil, menthol also has menthone and menthol acetate, which increases feeling cool. One study showed that a menthol rinse in addition to iced water had a positive effect on endurance on hot days.

It is important to note that most of the participants in these studies were male and, where applicable, athletes (rugby players). One study that did include women (<14%), stopped at age 42 years. So, if non-rugby players and women over 42, go out and make an ice sculpture during these extreme “heat domes”.