The Paleolithic standard for daily physical activity was about 490 calories (2.1 MJ), according to estimates by S. Boyd Eaton and Stanley B. Eaton in a 2003 article.
The Eatons estimated late Stone Age activity levels based on recent hunter-gatherer societies and skeletal remains from 50,000 to 20,000 years ago. In case you didn’t know, our bones reflect how much work we ask them to do. Heavy physical work loads over time lead to thicker, stronger bones, even changing the cross-sectional shape of long bones from round to oval.
From a diabetes viewpoint, the scientists expect that our prehistoric ancestors had excellent insulin sensitivity in view of their relatively larger muscle mass and high activity levels. They would have been less prone to develop type 2 diabetes.
Habitual high levels of physical activity of our ancestors put them in the same class as today’s elite cross-training athletes.
The Eatons suggest that replication of the Paleolithic activity level would require we exercise about an hour a day, not the 30 minutes recommended by some public health authorities.
Reference: Eaton, S. Boyd, and Eaton, Stanley B. An evolutionary perspective on human physical activity: implications for health. Comparative Biochemistry and Physiology: Part A Molecular and Integrative Physiology, 136 (2003): 153-159.