A pioneer Indian runner, Arun has been running multiday and ultra races since 2000 and shorter races since since 1991.
Baoli, Distt. Baghpat. UP. 24 February 1969
- 180 km in 23.25 hours on 28-29 July 2000 (solo run from Haridwar to Baghpat, UP)
- 270 km in 33.10 hr on 7-8 November 2001(solo run from Yojana Bhavan, New Delhi to National Ayurved Institute, Jorawar Singh Gate, Jaipur). Indian Record for the distance w.r.t. time taken.
- 138.172 km in IAU Asia 24 hr Track Championships in Taiwan on 2-3 March 2002.(9th place). First Indian representative in any 24 hr Ultra Marathon.
- 492 km in Australian 6 Day Race 17-23 Nov. 2002 & broke former Indian national record for 6 days race of 478 km made by Tirtha Kumar Phani in 1987. Thus, became first ever Indian to cross 300 miles in six days race (15th Place).
- 516 km in Self-Transcendence 6-Days race, New York 27 April -3 May 2003 and became the first Indian to cross 500 km in a 6-Days race (7th Place).
- 520 km in Copenhagen 6 Day Challenge, Denmark 3 – 9 August 2003 (4TH place).
Became first Asian to complete three 6-Days races within one year, and every time with a new national record.
- Finished IAU 100 Km World Cup 2003, Taiwan 16.11.2003. Became first ever Indian to participate and finish any 100 Km World Cup.
- 8. 501 km in International Six Day Running Championship, Mexico on 22-28 March 2004 (4th place in age category and 8th Place in general). First Indian representation in any Mexican ultramarathon championship.
- 532.8 km in Erkrath International 6-day race, Germany, 1-8 August 2004. Placed 15th. New Indian Record.
- 550 km in 122.45 hr Delhi to Chandigarh and back.
- MIR Marathon, Moscow, finished in 3.56.45 in –4 Deg. Celsius and Rain. (My first ever marathon)
- 153 km in 24 hr Open Championship of Russia, 7-8 May 2005. Became the only Indian in the history of Russian Ultramarathon.
- 558 km in 20th Australian Six Days Race, 20-26 Nov. 2005. 14th / 36. New Indian & South Asian Record. Got 26th place in the world rankings for 6-days races in 2005.
- 521 km in the Loutraki 7 Day Race, April 1-8 2006 (on a hilly course).
- 3.34.56 Marathon, Meerut 22.Dec.2006. (My second marathon)
- 370 km in 74.37 hrs i.e. Delhi-Shimla from 1 Feb to 4 Feb, 2007.