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When the heat is on, we sweat through our workout gear faster than you can say "Pilates." A tip-off from Tracy Anderson (she who trains Madonna) is to stock up on Topshop jogging bottoms and t-shirts, cut up and layer. "It's important to have your knees and elbows exposed when you exercise to gain energy," she advises.

Joggers, £22 and vest top, £6 (two for £9) from Topshop