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

Johannesburg residents lose more fluid through respiration and skin in the current dry winter than during summer rains, pushing recommended intake to 2.8 litres for active adults.

July marks the driest month on the Highveld, when relative humidity routinely falls below 25 percent in the afternoons and overnight temperatures drop to single figures. This combination accelerates water loss even for people who spend most of the day indoors, increasing fatigue and concentration lapses reported at workplaces across Sandton and Rosebank.

Parkrun groups that meet every Saturday at Zoo Lake in Parkview and the 5 km course through the Joburg Botanical Gardens in Emmarentia see several hundred participants each week who must plan fluid intake before and after their runs.

Local intake targets

Netcare hospitals in the northern suburbs record a seasonal rise in mild dehydration cases among outdoor workers and weekend athletes during July. The University of the Witwatersrand’s 2025 hydration survey of 1 200 Johannesburg adults found average daily consumption at 1.9 litres, well below the 2.8 litres now advised for the altitude and low-humidity conditions.

Practical choices on the ground

Tap water from Johannesburg Water remains safe and costs under R30 for a month’s supply at household level. Runners at Zoo Lake often carry 500 ml reusable bottles filled at the Emmarentia Dam public taps, while staff at Netcare facilities recommend adding a pinch of salt or a slice of lemon for those who struggle with plain water. After the morning Parkrun, participants are advised to drink another 500 ml within 30 minutes and to monitor urine colour before heading home through the security-gated suburbs.