Reena was born into a Hindu family from Punjab. Her father was a Punjabi while her mother was from Uttar Pradesh. She grew up in Darjeeling. She attended mountaineering courses at the Himalayan Mountaineering Institute in Darjeeling. She has taken part in and led several expeditions in the Himalayas. Her husband, Love Raj Singh Dharmshaktu is also a successful mountaineer, who has reached the summit of Mount Everest five times, besides climbing more than 38 other peaks.