An air ambulance was flown in after it is believed the man, thought to be in his 70s, suffered a cardiac arrest in Wheaton Aston, after attending the Wheaton Aston 10K this morning.
It is unclear whether the man was taking part in the race.
A spokesperson for West Midlands Ambulance Service said: “We were called at 11.10am to Fentonhouse Lane in Wheaton Aston to reports of an elderly male patient who had a serious medical condition.
“Two ambulances, an air ambulance, a private medical team and an off duty paramedic attended the scene.
“He was in a critical condition and received special trauma care and was transported to New Cross Hospital by land ambulance.”
Local resident Edwin Alden said: “It’s a beautiful, small village so something like this is quite extraordinary.
“This shows how important the air ambulance is, thank god for our emergency services, credit to them.
“The noise from the air ambulance was horrendous, so I grabbed my iPad and ran outside and saw everything, thank god for the ambulance’s fast response.
“I spoke to some of the race organisers outside my home and it seems as if the man was one of the runners.”