Variable in request does not update during while loop

Question

I initialize a date variable and a now variable. While date is smaller than now the code loops.

import ccxt
import datetime
exchange = ccxt.binance({ 'enableRateLimit': True })

date = 1502928000
now = int(round(datetime.datetime.timestamp(now)))

while date <= now:
    ohlcv = exchange.fetch_ohlcv('BTC/USDT', '1d', date, 1)
    print(ohlcv)
    date += 86400
    print(date)

At then end of the loop I update the date with one day, this works because I print the date and confirm the date changed.

But, the date within the request stays the same value. The response is always:

[[1502928000000, 4261.48, 4485.39, 4200.74, 4285.08, 795.150377]]
[[1502928000000, 4261.48, 4485.39, 4200.74, 4285.08, 795.150377]]
[[1502928000000, 4261.48, 4485.39, 4200.74, 4285.08, 795.150377]]
[[1502928000000, 4261.48, 4485.39, 4200.74, 4285.08, 795.150377]]
...

How do I update the date variable within the request?

Thank you