(sorry for the not great english in advance)
Liver health is important for people running a cycle...
people can't do blood test everyday, so here gives some signs that described by chinese medicine when your liver got problem...

the most relevant sign is the pulse on your wrist.
when your liver got problem, we call it 'string' pulse.
hard to explain, but try to put your middle three fingers vertically on wrist near your palm, feel the pulse. The artery should be kind of flexible, beating vividly but not over strong. if the artery seems tight and tense like a string, you got some problem. three possiblities: 1. you got a cold or flu, 2. you are very nervous recently; if they are all not the case, 3. your liver is screaming.

ok, i know it's a bit hard for beginners. but try to compare yourself with others, you will kind of know. String pulse is one of the most obvious pulse sign in chinese medicine diagnosis.

other signs:
liver can get two kinds of problem:
1. over heat liver:
signs:
short tempered, eyes and face more red, sides of chest slightly sore inside, urine deeper color than before, tongue coating yellow, bad breath, in the morning mouth feel dry, even feel mouth water kind of bitter. sleep is not good.

just some of them plus string pulse can already indicate that your liver is having a bad time.
If you don't know the pulse but you have many these symptoms, try to arrange a blood test for liver.

2. cold and wet liver:
signs:
loss apetite, gassy often, tongue coating white. sides of chest not feeling well.

if you have them and get string pulse, you are on the way to fatty liver.