RHR

When RHR means resting heart rate it is basically a measure of how many times your heart beats per minute when you're relaxed and not moving. In texts and chats, it's most commonly seen in conversations about fitness, especially when people are talking about their wearable health and fitness trackers (like smartwatches, rings and bands). They'll often also refer to their "HRV," "VO2 Max," and "fitness age."

In some corners of the online world, RHR has picked up a newer, niche meaning: "Random Human Response." It's used to point out replies that feel genuinely human — slightly messy, emotional, off-script, or imperfect — in contrast to polished, bot-like AI output. Someone might post "#RHR" to signal they think something wasn't generated, filtered, or optimized.

"Real Hot Runner" is another definition that is seen for RHR, especially on TikTok. It's used as a playful, politically-incorrect comment on pictures of attractive runners, both male and female.

RHR is an initialism, meaning each letter is pronounced separately ("R-H-R"), not as a word. It's not an acronym, as they form pronounceable words (abbreviations like FANG, GOAT, NASA, NATO, ROWE, TACO, YOLO). In short: if you can say it like a word, it’s an acronym. If you have to spell it out, it's an initialism.