Hydration in the local climate: how much and what to drink

Most Dubliners drink nowhere near enough water. That is the blunt conclusion of dietary assessments carried out this spring by Healthy Ireland, the national public health framework, which found that adults in the capital consume an average of 1.3 litres of fluid per day — well below the European Food Safety Authority's recommended 2 litres for women and 2.5 litres for men. The gap matters more in summer than almost any other season, even here.

July in Dublin is rarely scorching, but it is deceptive. Temperatures this week are sitting around 18–20°C, humidity is high coming off the Irish Sea, and the city's active commuter culture — cycling along the Grand Canal Greenway, running circuits of Phoenix Park, power-walking through Ranelagh — means bodies are losing fluid faster than people realise. Overcast skies suppress the thirst response. People do not feel hot, so they do not drink. That mismatch is exactly what dietitians at the HSE's primary care centres in Ballymun and Ringsend have been flagging to patients since April.

What the science says — and what Dublin's wellness community is doing about it

The EFSA's 2.5-litre daily target for men includes all fluid sources: coffee, soup, fruit, even bread. Plain water, however, should account for the bulk of it. Caffeine-containing drinks — the flat whites queuing out the door at 3fe on Grand Canal Street and the Americanos from Clement & Pekoe on South William Street — do contribute to overall fluid intake, contrary to the persistent myth that coffee dehydrates. A 2023 review published in the European Journal of Nutrition confirmed that moderate coffee consumption, up to four cups daily, has a negligible diuretic effect in habitual drinkers. The problem is that many Dubliners are substituting caffeine for water entirely rather than supplementing it.

Sports nutritionists working with Dublin-based running clubs, including Raheny Shamrocks AC and Clonliffe Harriers, recommend the simplest possible baseline test: check urine colour at the start and end of each day. Pale straw is adequate hydration. Dark amber means you are already behind. For anyone covering more than 5km in this week's humidity, an additional 500ml per hour of activity is the working rule, with electrolytes — sodium, potassium, magnesium — becoming relevant once sessions exceed 60 minutes. A 500ml electrolyte tablet from most chemists on Henry Street costs under €2, far cheaper than the premium isotonic drinks stocked in Spar and Centra.

Beyond water: what actually helps

Coconut water has become a fixture on the shelves of health retailers such as Nourish on Dawson Street, and it does contain meaningful potassium — around 600mg per 330ml serving. But it also carries roughly 15g of sugar per can, which makes it better suited to post-exercise recovery than routine daily sipping. For most people most of the time, filtered tap water remains the strongest recommendation. Dublin's tap water, supplied by Irish Water from the Poulaphouca reservoir in Wicklow, consistently meets EU Drinking Water Directive standards and requires no enhancement for the average adult.

Herbal teas deserve more credit than they typically get. Peppermint and chamomile infusions contribute to daily fluid totals without caffeine and without cost if made at home; a box of 40 peppermint bags from Fallon & Byrne on Exchequer Street runs to around €3.50. Bone broth and vegetable soups — long staples of the weekend markets at Marlay Park and Dún Laoghaire — also count. Hydration is cumulative across the full diet, not a single glass of water drunk dutifully at a desk.

The practical entry point for any Dubliner is a reusable bottle kept filled and visible. Research published by University College Dublin's Institute of Food and Health in 2024 found that proximity — having water within arm's reach — increased daily consumption by an average of 400ml without any other behavioural change. That single adjustment, scaled across the city's population of roughly 1.4 million, represents a significant public health shift. Start there, in whatever neighbourhood you happen to wake up in, and adjust from that baseline. Anyone with specific concerns about fluid intake or underlying health conditions should speak with their GP or a registered dietitian before making significant changes.