Lydia de Vega-Mercado was a sprinter who competed in the 1984 and 1988 Summer Olympic Games. She was Asia's fastest woman in the 1980s and bannered the country's Gintong Alay Program. Due to her records’ longevity, which lasted around 32 years each on average, she is considered as the Philippines' best locally produced sprinter. At the age of 19, she competed in her first Olympic Games in Los Angeles. In the women’s 100m event, she placed 6th in heat six and advanced to the quarterfinals where she came in 6th place in heat two but failed to qualify for the semifinals. In the 200m event, she placed 6th in heat one of the first round and failed to advance to the quarter finals. She competed again at the 1988 Summer Olympics in the 100m event. She came in 6th place in heat four of the first round and failed to advance to the quarterfinals.

De Vega first made an impact at the 1981 Southeast Asian (SEA) Games held in Manila with gold medal. performances in the 200 m and 400 m events, exceeding records set at the Asian Games. As Asia's sprint queen, she won the gold medal in the 100-meter dash in the 1982 New Delhi Asiad and duplicated the feat in the 1986 Seoul Asiad where she clocked 11.53 seconds. De Vega won the gold in the 100 meters in three SEA Games (1987, 1991 and 1993). She also topped the 200 meters event of the biennial meet in 1981, 1983, 1987 and 1993. She has twice won both the 100 and 200 meter golds in the Asian Athletics Championships (1983 and 1987). She holds both Philippine and Southeast Asian records with her personal best of 11.28 seconds. She also brought home a silver medal in the 200-meter race from the 1986 Seoul Asian Games.

1984 Summer Olympics, Los Angeles
1988 Summer Olympics, Seoul