Andrew Thomas’s life insurer knows exactly when he arrives at his local gym. The company is notified when he swipes his membership card, and 30 minutes later, it checks that he is still there, tracking his location through his smartphone.

The insurance company has a vested interest in keeping Mr. Thomas alive and well. In return for sharing his exercise habits, his cholesterol level and other medical information, Mr. Thomas, a 51-year-old medical publisher who lives in Johannesburg, earns points, which translate into premium savings and other perks. By staying in good shape, it is less likely that Discovery, his insurer, will have to pay out his life and disability policies.