Hey everyone I'd like to first admit that my cardio endurance is absolutely horrendous and I'm slowly but surely building it up. I recently started working out with a personal trainer who has been making me perform full body workouts. Here is an example of the last workout we did.
Push ups on DB's-15 reps
Jumping pull ups-15 reps
Sit ups-15 reps
Walking lunges w/ 20lb DB-15 steps one way and 15 steps back the other way
I did this for a total of 5 sets
By the time I hit my fifth set I was obviously sucking wind and tired as f*uck but I had this sudden rush of extreme tiredness and complete feeling of fatigue come over me, where for the life of me I could not stop yawning and just wanted to fall asleep right there. This has happen to me one other time about a month ago and it's the strangest feeling.
My question is, is this simply a result of my poor cardio endurance or a possible vitamin deficiency such as B12? When I run on the treadmill and I'm starting to feel tired I never start to yawn and get the sudden urge to fall asleep, could it perhaps be that I'm working both my cardio endurance and muscular endurance which is resulting in such extreme fatigue?