Im back and starting again

jmhurley87

Ive had to have 5 days off due to health reasons which has meant my diet and exercise has gone out of window but now im back.
Ive had to start 30ds on day 1 again, now before i burnt upto 400kcals ( using hrm) i was knackered early and was exhaustd by end but this morning i sped through it and pulse was lower and even though i sweated i found it easier..But i burnt 100kcals less ( due to lower pulse ) How does that work after 5 days of crap food and no exercise lol