The Person Who Drank Tea All Day and Wondered Why They Felt Awful

Linda made a cup of tea every hour. By her count, she drank constantly. What she had not accounted for: caffeine is a mild diuretic, and constantly drinking was not the same as consistently hydrating.

Linda is 52. She works from home as a freelance bookkeeper. She is a self-described "tea person" — she has always drunk tea throughout the day and would describe herself to anyone who asked as someone who "drinks plenty."

Over the last couple of years she had developed persistent low-grade headaches, particularly in the afternoons. She felt more tired than she had previously, and her concentration during complex financial work had become less reliable.

She did not consider hydration as a factor. She drank constantly. Tea, all day long. How could she be dehydrated?

Tea does count toward your daily fluid intake. A standard cup of tea (200–250ml) is predominantly water and does hydrate you. The caffeine content of a standard cup is relatively modest — around 50mg — and at these levels, the diuretic effect is mild. But Linda was drinking six to eight cups of tea per day, consuming 300–400mg of caffeine. At this level, the cumulative diuretic effect is more significant. And crucially, she was drinking nothing else.

When she completed her first perpHect check-in, her daily target came out at 2,100ml. She logged her intake over one day and found she was getting approximately 1,200–1,400ml — almost entirely from tea. She was running roughly 700–900ml below her actual requirement every day.

The change she made was modest: a glass of water with every other cup of tea. 400ml first thing in the morning before the first cup. Water with her lunch. She did not reduce her tea intake — she simply added water alongside it.

The afternoon headaches reduced significantly within the first week. She described the realisation as "genuinely embarrassing given that I thought I was the person who definitely drank enough."