In egypt, ancient kings were said to have ruled at times well over 50 years:
According to Africanus quoting Manetho, Menes (Narmer) ruled 62 years and Aha 57 years. Look at the regnal lengths of these kings from the Turin Canon:
II,17: Merbiapen (Anedjib) 74 years
II,18: Semsem (Semerkhet) 72 years
II,19: Kebehu (Qa'a) 63 years
II,20:Baw-Netjer (Hotepsekhemwi) 95 years
II,21: Kakaw (Reneb) - not recorded
II,22: Banetjer (Ninetjer) 95 years
II,23: Unknown name, 54 years - may be Peribsen/Sekhemib
II,24: Sened, 70? Years
Odd for a people that lived less than 4 decades. In sumeria, we have similar lengthy reigns perserved in the Kings Lists. Sargon and his descendant Naram-Suen each ruled 56 years, Queen Kug-Bau is said to have ruled 100 years and is attested in the records of several contemporary kings over the course of multiple decades. Dumuzid and Gilgamesh were each said to have ruled over 100 years apiece. Of course there are some kings mentioned who are said to have ruled mulitple centuries. (Not family dynasties because each of the sons in turn are enumerated.)
This wiki article dismisses more recent claims of great longevity as frauds:
A remarkable statement mentioned by Diogenes Laertius (c. 250) is the earliest (or at least one of the earliest) references about plausible centenarian longevity given by a scientist. The astronomer Hipparchus of Nicea (c.185—c.120 B.C.), who, according to the doxographer, assured that the philosopher Democritus of Abdera (c.470/460—c.370/360 B.C.) lived 109 years. All other account given by the ancients about the age of Democritus, appears to, without giving any specific age, agree in the fact that the philosopher lived over 100 years. This is a possibility that turns out to be likely given, not only by the fact that many ancient Greek philosophers are thought to have lived over the age of 90 (e.g.: Xenophanes of Colophon, c.570/565—c.475/470 B.C., Pyrrho of Ellis, c.360—c.270 B.C., Eratosthenes of Cirene c.285—c.190 B.C., etc.), but also because of the difference that the case of Democritus evidences from the case of, for example, Epimenides of Crete (VII, VI centuries B.C.) of whom it is said to have lived 154, 157 or 290 years, like it has been said about countless elders even during the last centuries, as well as in present time. These cases are most likely (or at least in most cases) exaggerations, if not deliberate frauds.
China and the hebrews also have similar traditions of long life many millenia ago. Note this quotation from Josephus:
"Now when Noah had lived 35O years after the Flood, and all that time happily, he died, having the number of 95O years, but let no one, upon comparing the lives of the ancients with our lives...make the shortness of our lives at present an argument that neither did they attain so long a duration of life...
"Now I have for witnesses to what I have said all those that have written Antiquities, both among the Greeks and barbarians, for even Manetho, who wrote the Egyptian history, and Berosus, who collected the Chaldean monuments, and Mochus, and Hestiaeus, and beside these, Hiernonymus the Egyptian, and those who composed the Phoenician history, agree with what I here say: Hesiod also, and Hecataeus, Hellanicaus, and Acuzilaus, and besides Ephorus and Nicolaus relate that the ancients lived a thousand years: but as to these matters, let everyone look upon them as he sees fit."
Many, many mythologies from around the world speak of a golden age in which the gods ruled and lifespans of multiple centuries were the rule, not the exception. This from the Hindu Law of Manu:
79. The before-mentioned age of the gods, (or) twelve thousand (of their years), being multiplied by seventy-one, (constitutes what) is here named the period of a Manu (Manvantara).
80. The Manvantaras, the creations and destructions (of the world, are) numberless; sporting, as it were, Brahman repeats this again and again.
81. In the Krita age Dharma is four-footed and entire, and (so is) Truth; nor does any gain accrue to men by unrighteousness.
82. In the other (three ages), by reason of (unjust) gains (agama), Dharma is deprived successively of one foot, and through (the prevalence of) theft, falsehood, and fraud the merit (gained by men) is diminished by one fourth (in each).
83. (Men are) free from disease, accomplish all their aims, and live four hundred years in the Krita age, but in the Treta and (in each of) the succeeding (ages) their life is lessened by one quarter.
84. The life of mortals, mentioned in the Veda, the desired results of sacrificial rites and the (supernatural) power of embodied (spirits) are fruits proportioned among men according to (the character of) the age.
85. One set of duties (is prescribed) for men in the Krita age, different ones in the Treta and in the Dvapara, and (again) another (set) in the Kali, in a proportion as (those) ages decrease in length
86. In the Krita age the chief (virtue) is declared to be (the performance of) austerities, in the Treta (divine) knowledge, in the Dvapara (the performance of) sacrifices, in the Kali liberality alone.
The problems of reconciling the seemingly long lives of the ancients with modern scientific understanding results in a plethora of explanations, from "its exagerration" to "different time basess were used". So why did practically every culture from the old world to the new world either exaggerate their claims or failed to recognize the course of a tropical year?