PC Jonathan Adams part-owns a horse with a racing syndicate and on one of the occasions was seen celebrating a win on television, the panel heard.
He faces three allegations of gross misconduct under "honesty and integrity" but denies lying.
If proven he could be dismissed from Gloucestershire Police. The hearing continues.
The panel was told that in September 2015 and April 2016, the probationary police officer had reported in sick and went to Nottingham racecourse to watch the horse he part-owned, named Little Lady Katy.
In June 2016 he reported in sick again and went to Royal Ascot to watch Quiet Reflection, another horse owned by his syndicate, win the Commonwealth Cup.
The misconduct panel was shown a television clip of PC Adams jumping around and celebrating which had been shown on Channel 4 Racing.
PC Adams said he had acted to avoid a "toxic" environment at Barton Street station in Gloucester where he worked as an investigation officer.
He described suffering stomach cramps, migraines and being in an emotional place which was affecting his irritable bowel syndrome.
He told the hearing if he had gone into work instead of going to Ascot he "wouldn't have lasted" and would have been "sent home, not fit for duty".
Stephen Morley, presenting the case for the force, told the hearing: "It is not good enough to report in sick and go on a jolly.
"He is a public servant and he is obligated to do what he could for the public."
Barrister Richard Shepherd, representing PC Adams, said the officer was of "impeccable character" who "did his best" to manage the symptoms of a "stress-related" condition.
The hearing heard PC Adams transferred to Gloucestershire Police in 2014 from the Civil Nuclear Constabulary.

They said in advance of their trip that if necessary, they would take the search into their own hands.
All debris thought to be from the plane has so far been found in east Africa.
The plane disappeared on a flight from Kuala Lumpur to Beijing in March 2014 with 239 people on board.
It is thought that missing jet is most likely to have crashed into the southern Indian Ocean.
Campaigner Grace Subathirai Nathan, whose mother was on the plane, is making the self-funded journey with six other MH370 relatives - three from Malaysia, two from China and one from France.
"It has fallen into our hands to take on this search upon ourselves," she told reporters at Kuala Lumpur airport.
"After repeated requests for mobilisation of a search along the east African coastline, nothing has been done to date."
The families of those on board the flight say that the search for wreckage has not been systematic and that some possible findings appear to have been ignored.
The search for MH370 has concentrated off Australia's west coast, but no debris has been found there. It is due to be suspended early next year unless it makes a significant new discovery.
So far, at least six pieces have been found in east Africa that are considered certain or highly likely to have come from the missing Malaysia Airlines flight.
The relatives say they will hand out brochures when in Madagascar that will provide advice to villagers on how to recognise aircraft debris.
Their trip will last until 11 December, a statement posted on Facebook by the group Voice 370 said.
Voice 370 said last month that it had "no other choice except to take it upon ourselves to do something to find answers and closure".
Malaysia is in charge of co-ordinating the collection of any suspected debris, most of which has been sent to Australia for examination.
The Malaysian authorities in September responded to criticism of delays in retrieving suspected debris, arguing that they were acting on possible discoveries and that everyone should "allow the experts to conduct the verification processes".
A police officer threw a "sickie" three times in order to watch horse racing, a misconduct hearing has been told.
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Relatives of those who died on board Malaysia Airlines flight MH370 are travelling to Madagascar to lobby for the search for debris from the missing aircraft to be expanded.