The organizing committee of the Tokyo 2020 Olympic and Paralympic Games said the change in timings had been done since the quadrennial event is taking place during peak summer.
The triathlon competition for men on July 20 and women on July 28 will be held at Odaiba Marine Park in Tokyo Bay at 6.30 a.m., one hour earlier than previously scheduled, according to the new timetable by the International Olympic Committee (IOC), reports Efe news.
Similarly, the timings for the mixed team relay on August 1 have been changed by an hour to 7.30 a.m.
Besides these categories, the organization has chosen to change the start time of the entire competition from the previously scheduled time of 8.30 a.m. to between 7.30 and 8 a.m.
"Part of a range of heat countermeasures, these changes were discussed with relevant stakeholders including the International Olympic Committee and the respective International Federations," said the organizing committee in a statement.
These changes were approved by the IOC on Wednesday, along with a new venue and dates for the marathon, which will now be held at Sapporo Odori Park in northern Japan instead of the Japanese capital due to concerns over extreme heat conditions.
The Odaiba Marine Park was also an area of concern. On several occasions excessive levels of E.coli bacteria were detected in its waters, prompting the organizers to take some experimental measures to attempt to solve the problem.
Moreover, several athletes who participated in a marathon swimming test-event in August expressed concern over the high temperatures and water quality.
( With inputs from IANS )