However, our expected healthspan (the amount of time for which a person is capable of substantial physical activity and not beset by ailments) has gone up considerably in the last few centuries. Perhaps the relatively few people who made it to old age in hunter-gatherer societies might have had similar healthspans, but they constituted a dramatically smaller fraction of the total populace. The average 35 year old today has decades longer of healthy, productive living to look forward to than the average 35 year old 300 years ago (sources available in this book) and while people occasionally remark on, say, 50 being the new 30, it doesn't seem to leave most people dazzled or mentally unequipped for their new environment.