Hello, Welcome to Health Care Magic. Thanks for writing. I am Dr.Saddiq-ul-Abidin. I have read your question completely, I understand your concern and will try to help you in best way possible. Yo make you understand things by yourself I will first explain to you how cardiac pain and cardiac event is characterized.I would describe the pain first because just fatigue in a cardiac event is something rare unless one is uncontrolled diabetic or has a severe neuropathy.Usually there is pain. cardiac pains are like: 1- They are NEVER sharp excruciating pains,they are dull pains like soar muscles or a compression. 2- They start with work out and go away as you are at rest. 3- When its paining they in most case get relieved by a nitroglycerin tab under tongue. 4- Regular work out cardiac pains (angina) usually show up in stress testing. 5- They are very rarely present in men below 40. 6- They never Get worsened by food intake, they stay the same. 7- They don t change in intensity with breathing. Or changing body position. 8- They can not be pinpointed usually they are spread over an urea of chest. 9- Usually less than 30 mins in duration. Your event doesn t look like cardiac it might have other reasons with it. 1) Your food intake wasn t good today. 2) You didn t take enough carbs. 3) Your salt intake wasn t good. 4) Your fluid intake could have been less than required. 5) You might have not slept well in night. 6) Mental stress could have done this. 7) You might have worked out immediately after a meal. A single event of fatigue doesn t signify much it is necessary to sleep well.. to be fresh and stress free mentally to take enough pre peri and post workout energy (carbs) and to take good amount of fluids and salts, any thing lagging can cause fatigue so I would ask your not to panic and take care of the things I mentioned. I hope this answered your question.If you have more queries I am happy to answer.Otherwise rate and close the discussion Regrads. Dr.Saddiq ul Abidin M.B.B.S(Licensed Family Physician) Resident Medicine.