To stir up the mix, the next few days are predicted to be scorchers of 40 degrees or more. 'This has been one of the hardest marathons I've joined so far,' says Tom Simmat, the 59-year-old leader on handicap after yesterday's leg.

The heat is making the Marathon even trickier, according to Red Cross health support team leader Adam Dent, who's working with more than 50 first aiders, nurses, paramedics, masseurs and a doctor to keep an eye on paddlers' health.

'We'd rather give advice about health and wellbeing, than waiting for paddlers to come to us sick,' he said. 'Our first aid volunteers last night distributed information on how to stay hydrated and are encouraging people to start drinking water early in the day. If you drink only when you feel thirsty, it's too late.'

While the heat and fatigue is a challenge for some paddlers, the diabetic team members of HypoActive have another pressing issue to contend with.

'We have to look out for each other, we're fatigued and it could lead to a hypoglycemic (hypo) attack' said team member Dan Seller.

At the end of the second day, 59-year-old Tom Simmat from Sydney still leads the handicap. Partners Kim Willocks and David Provan from Patterson Lakes took fastest outright time. Echuca policeman Rod Clark and Ian Newland from Queensland are in second place in the handicap, with Stuart Nicol from Werribee and Echuca's Tony Bond in third.

In the schools section, Woodleigh Water Rats from Baxter still lead, with Wellers A and Trinity Green following closely.

Today is the half-way mark for the five-day event, which started in Yarrawonga on 27 December, and finishes in Swan Hill on New Year's Eve. Today, paddlers make their way from Picnic Point to Echuca 76 km down river.

Funds raised by paddlers and their dedicated support crew help Red Cross deliver services to vulnerable people in Victoria, from reuniting families who have been separated by war or disaster to helping communities cope after major emergencies.