The notion has its roots in ayurveda. “Your internal temperature is 98 degrees; therefore, we should drink our water with a similar temperature for absorption,” explains Sahara Rose, an ayurvedic expert and author of the modern ayurvedic cookbook Eat Feel Fresh. “When we drink cold water, our body has to expend a lot of energy to increase the temperature of the water to our internal organs, leaving us with less energy for healing and mental function.” Many ayurvedic practitioners—Rose among them—recommend consuming only warm water or even hot water (or tea) to keep digestion at its optimal state. Well—kind of. “As you might guess, there is little scientific research on the benefits of drinking warm water, although it’s advocated in many cultures,” says Amy Shah, M.D., a Columbia and Harvard-trained doctor and mbg Collective member. “The only thing that really is plausible scientifically is that by drinking cold water, you are constricting your blood vessels and may not have good absorption, whereas when you drink warm water, your blood vessels are more dilated.” She notes that this is why tea is recommended by many doctors for patients with a cold. “The blood vessels dilate and the mucus travels faster out of your nasal cavities1,” she says. Plot twist, though—despite the lack of Western studies, Shah herself is an advocate for eschewing ice water. “After all of my medical training, I’ve come to realize there’s a lot that we don’t know, especially when it comes to gut health and the immune system. These are areas that we don’t understand well with our traditional medical model.” According to ayurveda, Shah has primarily vata energy, which is one of the types that especially benefits from having warmer liquid. “I found this to be so beneficial for me and for my patients who also have this tendency.” She also notes that her patients who have sluggish digestion benefit from consuming warmer beverages. Another benefit of warm water? It provides the perfect medium for steeping herbs, spices, and teas, which can further aid in digestion and gut health. Rose makes a version with cinnamon, cumin, coriander, and fennel. “It’s so balancing for your digestive system and delicious,” she says. In general, doctors stress that the most important thing is consuming an adequate amount of water daily—meaning that the method that will get you to drink up is the best one for your body. That said, if you’re suffering from gut or digestive issues, or if you want to explore the healing modalities of ayurveda, it might be worth sipping room temperature or warm water for a week or two and seeing how you feel. At the very least, you’ll avoid a brain freeze.