Other causes of nausea include side effects from medications, pain, pregnancy and morning sickness, seasickness, viral infection, alcohol toxicity, and disease of the brain, esophagus, stomach, gallbladder, liver, pancreas, and intestine.
so roosevelt was able to win more than two terms because there was not yet a formal term limit on the presidency and the unique conditions when he ran for his third and fourth terms made his arguments for breaking with tradition acceptable to a majority of american voters
The Amendment that makes this restriction was put in place after FDR was in office, and explicitly exempted him from it's restrictions. All previous Presidents just never ran for a 3rd term because of the example Washington Set. So, barring another Amendment (not very likely), FDR will be the only US President to ever serve more than 2 terms.