Large Transport; Low Wing; 2 Turbojet Eng
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 189; Flight Crew Type 8500
Physiological - Other
Flight Deck / Cabin / Aircraft Event Illness / Injury
Flight Crew Returned To Gate; General Flight Cancelled / Delayed
Human Factors
While pushing back from gate; the Captain began to feel lightheaded and shaky. Symptoms got somewhat worse and did not abate during taxi out. Captain drank orange juice; ate some crackers; and held the aircraft at the [runway] hold short to see if he would begin to feel better. After several minutes the Captain decided that he was not fit to fly this leg and returned to the gate to be replaced. These symptoms were most certainly caused by low blood sugar as a result of a strenuous workout at the hotel and the Captain failing to eat enough food during the day. A contributing factor was that due to the five hour flight; the Captain lost track of the time of day and failed to realize that it was past midnight body time and he was long overdue for a meal. Preventative Measures: This was a case of the Captain enjoying a strenuous workout and being made ill by an insidious combination of exercise; lack of food; a long day; and not recognizing the late hour of day due to multiple time zone changes. It was an embarrassing situation really; and one from which the Captain learned many lessons. In terms of ASAP applicability; sometimes it's easy to forget in this job what strange situations we place our body in. We don't always sleep as well as we want to in hotels. Even when we attempt to sleep long; we often wake at the time that would be normal at home. This was the case today. We then eat and workout at the hotel on a fairly normal schedule; but the day turns strange when we report in the middle of the afternoon for a long PM duty period. A long haul flight to the west coast keeps us in bright sunlight even though our bodies know it to be well into the night. If we are not careful to keep ourselves properly fueled and hydrated the awkward and inconvenient situation described here can occur.
Air carrier Captain reported returning to the gate after feeling ill on taxi-out; probably related to low blood sugar.