At a press event in Covington, Kentucky, the 81-year-old paused for more than 30 seconds when asked whether he would run for-re-election in 2026.
Aides attempted to prompt the senator, but it took several more seconds for Mr McConnell to recover.
Mr McConnell, who leads the Republican party's narrow minority in the upper chamber of Congress, was admitted to hospital for a week after suffering a concussion and a fractured rib following a fall outside a Washington area hotel in March.
He was transferred to a rehabilitation facility and did not return to the Senate until mid-April.
After the freezing incident in July, US media reported that Mr McConnell has endured at least three other falls since February.
This latest episode will again raise questions about the health of the Kentucky senator heading into what will be a busy autumn legislative session, as Congress attempts to avoid a partial government shutdown at the end of October