Maximal heart rate during work in older men

Nine 56–68-year-old male subjects performed muscular work up to maximal loads on a bicycle ergometer while breathing both ambient air and oxygen. Heart rate increased to an average maximum of 163/min. The maximal O 2 intake averaged 2.24 l/min. and the blood lactic acid concentration 85 mg/100 ml. In no case was the maximal heart rate higher when breathing O 2 than when breathing air. This low maximal heart rate in older people probably limits the capacity for O 2 intake. Four subjects were able to work for about 1 hour without any sign of exhaustion on a work load requiring an O 2 consumption of about 50% of their maximal aerobic work capacity.