The Queen was back at her desk on Thursday after an overnight stay in hospital on Wednesday sparked national concern.
Buckingham Palace were forced to confirm the visit after The Sun broke the story but was quick to reassure the public that the monarch “remains in good spirits”.
They added that the Queen is undertaking light duties this weekend.
The reason behind the hospital visit has not been disclosed but the Queen as photographed walking her dogs before a car took her to hospital in the afternoon.
She has been pictured using a walking stick “for comfort” recently and have given up alcohol under doctor’s orders.
The palace has said it will not provide a running commentary on her health but the reason for the Queen’s hospital visit could simply be fatigue.
Since returning from her summer break at Balmoral the Queen, who is 95, has undertook 19 engagements.
These included the opening of the Scottish and Welsh parliaments, sending the Commonwealth Games baton on its way from Buckingham Palace, marking the Royal British Legion’s centenary at Westminster Abbey and welcoming New Zealand’s incoming governor-general, Cindy Kiro, with a video call from the castle.
There has also been a packed private programme of lunches and dinners with family and friends because the Queen does not want to dine alone, the Sunday Times reports.
One courtier told the paper: “It has been too much”.
While another source admitted: “She is knackered.”
It is little wonder that that the Queen has expressed a desire to keep busy after losing the Duke of Edinburgh in April after 73 years together.