Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you:
You look down and very low to the ground is a man, looking up at you. Your friend is there too, but you don't know this little man. Your friend says "He coo', he coo," referring to the low to the ground man.
I like a guy with a low voice.
Our daughter is a little shorter than average.
"Hey, Yuki. You don’t look so good." "Yeah, I know. I was diagnosed with hypotension." "What’s that?" "It just means that my blood pressure is really, really low." "How low is that?" "Well, this morning was about 80/40."