A Porthcawl RNLI crew with a medic and the coastguard search and rescue helicopter were sent to Sker Beach, near Kenfig Nature Reserve, at 12:50 GMT on Sunday.
Crewman Chris Page said the rider had head injuries and was very cold from lying unconscious on wet sand.
She was treated before being flown to Cardiff's University Hospital of Wales.

A second bus was hit by a suicide bomber elsewhere in the city, injuring two soldiers and two civilians.
The Taliban said they had carried out the attacks.
The blasts come a day after Afghan and US officials signed a deal letting US troops stay in Afghanistan after the end of 2014.
The agreement was authorised by new Afghan president Ashraf Ghani, who was sworn in on Monday.
On that same day, two bombs killed at least 15 people in Kabul and Paktia provinces.
Mr Ghani's predecessor, Hamid Karzai, had refused to sign the deal because of a disagreement with the US.
The attack on the army bus took place in western Kabul, and largely destroyed the bus.
"I was walking down the road when a huge explosion occurred," shopkeeper Sanaullah Khan told Reuters.
"Right after the blast, I saw dust and smoke rising from the area and then I escaped."
The second attack took place in northeast Kabul.
The Taliban claimed responsibility for both attacks on Twitter, saying they were a continuation of an offensive which started in the summer.
Under a US-brokered unity deal Mr Ghani shares power with runner-up Abdullah Abdullah who becomes chief executive. The Taliban has called the deal a "US-orchestrated sham".

Woods, 41, is recovering from a fourth back operation since April 2014.
The American 14-time major winner was breathalysed in Florida in May after being arrested on suspicion of driving under the influence.
He denied alcohol was involved and said it was down to "an unexpected reaction to prescribed medication".
In a statement released on social media, Woods said: "I'm currently receiving professional help to manage my medications and the ways that I deal with back pain and a sleep disorder.
"I want to thank everyone for the amazing outpouring of support and understanding, especially the fans and players on tour."
Woods has not won a tournament anywhere since 2013, while his title drought in major championships dates back to 2008.
Last December, he came back after 15 months out injured but has not played since his back problems recurred in February.
A month ago, he wrote that his latest surgery had relieved pain and that he had not "felt this good in years".
Four days later he was arrested on the driving charge, which he is due to answer in court in Palm Beach County on 9 August.
A woman has been airlifted to hospital after falling from a horse on a Bridgend county beach.
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At least seven Afghan soldiers have died and many were injured after a suicide bomber targeted a bus carrying troops in the Afghan capital Kabul.
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Former world number one Tiger Woods says he is getting "professional help" to manage medication for pain and sleep loss as he tries to return to fitness.